Alberta's largest sector union is seeking an injunction against the provincial government to allow a wage arbitration hearing to proceed by the end of June, as stipulated in collective agreements.

In a statement of claim filed in Court of Queen's Bench Monday, the Alberta Union of Provincial Employees is also challenging the United Conservative government's Bill 9 on constitutional grounds.

The controversial bill defers wage arbitration talks for 180,000 nurses, teachers and government workers until Oct. 31.

It passed third and final reading at 7 a.m. Thursday after an all-night session.

The union says wage arbitration hearings were cancelled after government lawyers told their representatives that the bill would receive royal assent on Friday.

The bill hasn't received royal assent as of Monday morning.

"We were lied to," AUPE president Guy Smith said in a written statement.

"Bill 9 is not yet law. We could have gone ahead as scheduled but instead we lost key arbitration meetings because the government gave us false information.

"This is bad faith bargaining. It's outrageous, and further proof the UCP government has no respect for working Albertans or the law."

Reporters asked Finance Minister Travis Toews to respond to the union's allegations about the information they were given by government lawyers.

Toews was asked about the issue numerous times and responded with the same answer.

"We're expecting this bill to be proclaimed very soon and again we've been clear with its intent," Toews said.

The government wants to hold off on wage arbitration talks until it receives advice on Alberta's finances from a panel chaired by former Saskatchewan finance minister Janice MacKinnon.

Union leaders say the bill is a precursor to legislated wage rollbacks this fall.