HALIFAX -- Nova Scotia's Liberal government finally moved on a contentious piece of labour legislation Tuesday, effectively imposing a wage package on the province's 75,000 public sector employees and drawing a fiery response from the union representing the majority of them.

Premier Stephen McNeil said the proclamation of the Public Services Sustainability Act was being done in the "best interests of Nova Scotians," but the union president called that insulting.

"It's the arrogance of this government that just really cooks my goose," said Jason MacLean, president of the Nova Scotia Government and General Employees Union (NSGEU).

The act was passed in December 2015 to ensure third party arbitrators could not bind the government to wage settlements. At the time, McNeil promised it would not be brought into force until it was needed.

The government's move came two weeks after the Nova Scotia Government and General Employees Union (NSGEU) -- the province's largest -- filed for arbitration on behalf of nearly 8,000 civil servants after last-ditch conciliation talks broke down. Those workers included corrections, child welfare and court employees.

The new act would also cover thousands of other workers, including those in health care who are yet to reach new deals with the province.

"I've made it very clear that an unelected, unaccountable arbitrator will not determine the taxpayers' ability to pay," McNeil told reporters.

The act doesn't end arbitration but does limit arbitrators from making awards that exceed the wage guidelines.

It sets a wage pattern of three per cent over four years that will allow increases of one per cent in the third year of the contract, followed by 1.5 per cent in the fourth year and 0.5 per cent on the final day of the package.

A retirement allowance is also frozen retroactive to April 1, 2015. The so-called public service award is a lump sum payment for retiring workers with at least 10 years of service.

New employees will no longer be eligible for the payment under the government's change.

MacLean lashed out at the government's move, even though he said he wasn't surprised by it.

"You have Stephen McNeil who I believe is a snake, and then you have (labour relations minister) Mark Furey who is basically the dishonourable middle man. These guys are taking control of where labour goes," MacLean said in an interview.

MacLean pointed out his union members are also taxpayers who will now have less money to spend as the province struggles with a sputtering economy.

"And now he (McNeil) took away their public service award which is adding insult to injury because it is something that was freely and collectively bargained," he said.

McNeil said the act will be referred to the Nova Scotia Court of Appeal under the Constitutional Questions Act to obtain an opinion.

He said the government is confident the law will stand up to constitutional scrutiny.

"We believe the constitution says that everyone is entitled to open and free collective bargaining. We believe we've gone that process. We have been at the table many times with our (bargaining) units," he said.

MacLean said the union would wait to see how the Nova Scotia court rules, adding that the union also stands ready to mount a Charter of Rights challenge before the Supreme Court of Canada.

"The NSGEU will not rest and they will make this government miserable," said MacLean.

The act exempts groups that already have agreements, including judges, doctors, physician residents, teachers, and about 15,000 management and non-union positions.

McNeil was asked whether he believed his party's re-election May 30 was an endorsement of his approach to the labour file.

"This has been an endorsement on the direction of our government. We also know that Nova Scotians wanted our government to live within its means and they believe the approach that we were doing was a positive one."

Progressive Conservative Leader Jamie Baillie said the government's move is part of "an expensive game."

"We are now condemned to years of legal costs," Baillie said. "Millions of dollars that's not going to go to doctors or health care because the government couldn't get the job done in the normal way and has resorted to this kind of gamesmanship."

NDP critic Susan Leblanc said the government's court referral signals a lack of confidence in legislation that she said will further sour labour relations in the province.

"It basically says we don't want to go any further in these negotiations, this is what we want, this is what's going to happen, we're allowed to do this, we are going to push it through. It's a bullying tactic."

Earlier this year the government drew the ire of more than 9,300 public school teachers when it ended a 16-month contract dispute by passing legislation that imposed a contract settlement.

The bill also gave teachers a three per cent wage increase over four years and froze their long service award retroactive to July 2015.

It came after teachers had previously rejected three tentative agreements.