Union members at Statistics New Zealand have imposed a work to rule regime and a ban on overtime over a proposed new pay system.
The Public Service Association says some field personnel will also withhold or delay the reporting of survey results.
PSA national secretary Richard Wagstaff says Statistics New Zealand is trying to force employees to adopt a new pay system, without consulting them first.
He says the new system is unfair and some staff will benefit greatly, while others will not.
Mr Wagstaff says it also undermines redundancy and long service leave for some people.