Timelines at the End of the Tax Year (Employees)

Automatically issued income tax assessments processing timeline

1 April to late-May – Gathering information

IRD will be gathering income and tax information from the employees employer (or income provider), bank and investment providers.

Late-May to end of July – Income tax assessments and requests for more information sent

IRD will send these between late-May and the end of July, so not everyone will get theirs at the same time.

After the end of July

The employee may receive theirs after July if the employee is required to provide more information, or IRD are waiting for other information from the employee’s employer (or income provider) before IRD can finalise the employee’s income tax assessment.

Reference: here