Vanuatu's Council of Trade Unions says a change to the Public Service Act is a recipe for instability in the public sector.
Last week, parliament passed in principle an amendment to the Act, which means the head of public agencies will no longer be appointed by the Public Service Commission, but by ministers.
Transparency International says it removes the independence of the public service.
The general secretary of the Council of Trade Unions, Ephraim Kalsakau, says there was no public consultation on the changes.
"In the last nine months I think we've had five or so changes of Government. That would have meant that if that law was in place, the DGs would have been changed five times. And that is not stability, it's fuel for instability."
Ephraim Kalsakau says the post of Director General was created so there would be continuity even when ministers changed, and the move is a step backwards.