Legal action is being threatened against the tax department, with a public workers' union saying long-time staff are being made to take psychometric tests while reapplying for jobs.
Inland Revenue in July announced it would be cutting 1500 jobs - 30 per cent of its workforce - with 4200 jobs affected by changes.
The Public Service Association says the department has been calling on its staff to reapply to retain employment, often in jobs they have been doing for many years.
As part of the reapplication process, Inland Revenue has been coercing staff - including those who had been with the department for up to two decades and were experts in their fields - to take psychometric testing, PSA national secretary Erin Polaczuk said.
Calling the tests "absurd and wasteful", Ms Polaczuk is threatening to take the department to the Employment Court for a violation of its employees' human rights.
A more rational way to test a person's suitability would be to consult their years of existing performance reviews and evaluations with the department, she said, rather than take to a "pseudo-scientific" test.
"We're concerned that psychometric testing is being used as a kind of Trojan horse to make whatever unilateral and arbitrary staffing decisions that senior managers want," Ms Polaczuk said.
Comment has been requested from IRD.