Hundreds of public servants will face a choice between pay freezes or sackings under the state government's contestability policy, the Together Union says.

Secretary Alex Scott said a quarter of Work Cover staff, about 200 people, would need to decide whether to accept a redundancy or a classification downgrade by Friday.

By accepting the classification downgrade, workers would be agreeing to freeze their pay for at least 10 years, Mr Scott said.

The union has sought orders from the Industrial Relations Commission to push back the deadline. The hearing on the matter is scheduled for Friday.

“This is clearly a taste of what is to come under the government's privatisation and contestability agenda,” Mr Scott said.