The Public Service Association says a restructuring plan affecting about 6000 staff at the Ministry of Social Development lacks transparency, and has some people worried about their futures.
The Ministry proposes to streamline Work and Income and other services, which it said would involve disestablishing some jobs.
Acting national secretary of the Public Service Association Glen Barclay said staff were worried about old job descriptions being used to create their new jobs under the new structure.
"Members were feeling that they weren't spoken to about their job and what they actually do, that the like for like positions, where functions are shifted into the new structure, they feel that the process identifying that was inconsistent."
The PSA said few people believed the proposed changes will lead to better services.
However, Work and Income deputy chief executive Debbie Power said there had been a consultation process with staff and their feedback would be considered when finalising the new structure.