When migrating to a new payroll platform becomes a compliance nightmare
Switching payroll systems should be straightforward. Export your data, import it into the shiny new platform, and carry on as usual. Simple, right?
Not quite.
Every year, New Zealand businesses make the leap to new payroll software – lured by promises of automation, better reporting, or cost savings. Yet many discover too late that the transition has created a tangled mess of missing data, incorrect leave balances, and compliance breaches they didn’t see coming.
The problem isn’t usually the new system itself. It’s what gets lost, misunderstood, or misconfigured along the way.
The Compliance Time Bomb Sitting in Your Data
New Zealand’s employment legislation is unforgiving when it comes to payroll accuracy. The Holidays Act 2003 alone has tripped up organisations ranging from small businesses to government departments, resulting in remediation bills running into the millions.
When you migrate payroll systems, you’re not just moving numbers. You’re transferring a complex web of entitlements, calculations, and historical records that your new system must interpret correctly from day one.
Here’s what many businesses fail to realise: your old system may have been calculating things in a particular way, sometimes correctly, sometimes not. If you don’t understand those calculations before you migrate, you risk either replicating errors or creating entirely new ones.
Critical Data That Often Goes Missing
Leave Balances and Entitlement Dates
Under the Holidays Act 2003, employees accrue annual leave based on their anniversary date, not the calendar year. Alternative leave (time off in lieu for working public holidays) has different rules again. Sick leave entitlements reset at specific intervals.
When migrating systems, it’s frighteningly common for:
- Anniversary dates to be incorrectly recorded or defaulted to the hire date
- Leave balances to be imported as a single figure without the underlying entitlement history
- Alternative leave balances to vanish entirely because the new system handles them differently
- Sick leave entitlements to reset incorrectly, potentially short-changing employees
One incorrect anniversary date doesn’t just affect one leave calculation – it creates a compounding error that grows with every pay period.
Average Daily Pay and Relevant Daily Pay
The Holidays Act requires employers to calculate leave payments using either Relevant Daily Pay (RDP) or Average Daily Pay (ADP), depending on the circumstances. Your old system likely stored the data needed for these calculations in a specific way.
If your new system expects that data in a different format – or worse, if you simply import current balances without the underlying payment history-you lose the ability to calculate these figures correctly.
The result? Employees may be underpaid for annual leave, sick leave, or public holidays. And under New Zealand law, that’s a breach you’re liable for, regardless of whether you intended it.
PAYE and Tax Code History
Inland Revenue requires accurate PAYE reporting through payday filing. Your employee tax codes, student loan deductions, KiwiSaver contributions, and ESCT rates must transfer accurately.
Common migration failures include:
- Tax codes reverting to default settings
- KiwiSaver contribution rates being incorrectly applied
- Student loan deduction flags being lost
- Historical filing records not being accessible for IRD queries
These errors don’t just create compliance issues – they can result in employees facing unexpected tax bills or incorrect KiwiSaver contributions that take months to rectify.
Employment Agreement Terms
Many payroll systems store information about individual employment terms: allowances, overtime rates, specific leave arrangements, or enhanced entitlements negotiated as part of an employment agreement.
If your new system doesn’t have fields for these variations, or if the person setting up the migration doesn’t know they exist, those terms can simply disappear. You then end up breaching employment agreements without realising it.
The Knowledge Gap Problem
Here’s the uncomfortable truth: most payroll migrations fail not because of technical issues, but because of knowledge gaps.
You don’t know what your old system was actually doing. Many payroll platforms make calculations behind the scenes. If you’ve never dug into exactly how your current system calculates Relevant Daily Pay, or how it handles leave for employees on variable hours, you won’t know whether your new system does it the same way—or correctly.
You don’t know what your new system needs. Every platform has its own data structure, terminology, and assumptions. A field labelled “leave balance” in one system might mean something subtly different in another. Without understanding both systems thoroughly, accurate mapping is guesswork.
You don’t know what you don’t know. The most dangerous errors are the ones you can’t see. If nobody in your organisation fully understands the Holidays Act calculations, how would you recognise when they’re wrong?
Real Consequences for New Zealand Businesses
The risks here aren’t theoretical. In recent years, major New Zealand employers—including government departments, councils, and well-known private companies—have faced significant remediation exercises after discovering systemic payroll errors.
Common consequences include:
- Back-pay obligations stretching back six years (the limitation period for Holidays Act breaches)
- Labour Inspectorate investigations which can result in penalties and public naming
- Damaged employee relationships when staff discover they’ve been underpaid, sometimes for years
- Significant remediation costs including external consultants, system corrections, and the administrative burden of recalculating thousands of pay periods
For small to medium businesses, even a relatively minor Holidays Act breach affecting a handful of employees can result in back-pay obligations of tens of thousands of dollars – plus the time and stress of sorting it out.
How to Migrate Safely
If you’re considering a payroll system change, or you’re already partway through one, here’s how to protect your business.
Before You Start
Audit your current system. Before exporting anything, ensure you understand exactly how your current payroll calculates leave, handles public holidays, and manages the various entitlements required under New Zealand law. If you’re not confident, get expert help.
Document everything. Create a comprehensive list of every data field, every custom configuration, and every employee-specific arrangement in your current system. This becomes your migration checklist.
Understand your obligations. Refresh your knowledge of the Holidays Act 2003, the Employment Relations Act 2000, and your Inland Revenue obligations. If your HR or payroll team can’t explain how Relevant Daily Pay should be calculated, that’s a red flag.
During Migration
Map data fields carefully. Don’t assume that similarly named fields mean the same thing. Work with both your old and new system providers to ensure accurate data mapping.
Migrate historical data, not just current balances. Where possible, transfer the underlying transaction history, not just snapshot figures. This preserves your ability to recalculate and audit.
Test thoroughly. Run parallel payrolls before going live. Compare outputs line by line for a sample of employees with different circumstances – part-timers, those on parental leave, employees with enhanced contractual entitlements.
After Migration
Audit early and often. Don’t wait for an employee complaint or an IRD query to discover problems. Conduct spot-checks on leave calculations and PAYE accuracy in the first few pay periods.
Keep your old records. Maintain access to your previous system’s data for at least seven years. You may need it to answer queries, support remediation, or provide evidence to regulators.
Stay vigilant. System migrations often surface pre-existing errors that were already in your old platform. Be prepared to address these as part of the transition.
When to Call in the Experts
Payroll migration isn’t a DIY project for most businesses. The intersection of technical system knowledge and New Zealand employment law expertise is specialised, and getting it wrong is expensive.
Consider engaging professional support if:
- Your workforce includes part-time, casual, or variable-hours employees (where Holidays Act calculations are most complex)
- You have employees with individualised contractual arrangements
- You’re migrating from a legacy system with limited export capabilities
- Your internal team lacks confidence in Holidays Act compliance
- You’ve previously had payroll issues or haven’t audited your systems recently
The cost of expert guidance during migration is almost always less than the cost of fixing errors after the fact.
The Bottom Line
Switching payroll systems can deliver genuine benefits—better functionality, reduced costs, improved reporting. But those benefits only materialise if the migration is done properly.
The data you migrate, and how you migrate it, determines whether your new system will be an asset or a liability. Understanding both your legal obligations and your technical requirements isn’t optional—it’s essential.
Before you make the switch, ask yourself honestly: do you truly understand what your current system does, what your new system needs, and what New Zealand law requires?
If the answer is anything less than a confident yes, it’s time to get help before you proceed.
Paymasters specialises in New Zealand payroll compliance and system migration support. If you’re planning a payroll transition, or concerned about your current setup, contact us for a confidential discussion.