COUNCIL staff are nearing a "tipping point" where simmering frustration about pay and treatment boils over into widespread strike action, union leaders have warned in the wake of John Swinney's heavily criticised budget plans.

The SNP Finance Secretary announced on Thursday that he was ending a two-year pay freeze for civil servants and NHS staff, with a "modest" salary rise next year capped at 1%.

However, this does not apply to almost 300,000 council workers, who have their own pay negotiations with the 32 councils in the Convention of Scottish Local Authorities (Cosla), which were given a real-terms cut in their budget by Swinney.

A 1% pay rise for non-teaching council staff next year would cost more than £50m. Council workers have already been rebuffed by Cosla over this year's demand for an extra £1000 plus a "living wage" of £7.20 an hour. Cosla has also refused to implement deals given to other public-sector workers, such as a £250 pay rise for those earning under £21,000 and a policy of no compulsory redundancies, leading to feelings of unfair treatment among council staff.

Until now, they have grudgingly accepted the pay freeze, knowing that demanding higher salaries could force councils to cut services and lay off staff to pay for them.

One in 10 council posts has already disappeared since the recession began in 2008.

But Unison's Scottish organiser Dave Watson said that instead of suffering in silence next year, staff anger over job losses, pension changes, higher living costs and unfair treatment could converge to bring about a tipping point.

He told the Sunday Herald: "History shows that people put up with things for a good while then say 'Right, we've had enough of this'. If you look back over the past 30 to 40 years of industrial relations, it's been a roller-coaster. Local-government and public-sector pay falls behind the private sector, and then you have a catch-up exercise.

"But it's going to be very difficult for councils and other parts of the public sector to finance that catch-up because this recession is as deep as we've seen since the 1920s."

Alex McLuckie, GMB Scotland senior organiser, said there is a growing feeling among council staff they are getting a raw deal.

"Our members are starting to say 'No, enough's enough'. If Cosla come back and say they want another wage freeze in 2013-14 our members will be up for a fight."

Dave Moxham, deputy general secretary of the STUC, added: "I would suggest local-government workers are pretty depressed and probably quite angry and there's the potential for that to be directed [into action]. There's a feeling that we get these public-sector pay policies from John Swinney, but no encouragement for local government to do anything in particular."

Council staff represent just under 60% of all workers in the devolved public sector, and have borne the brunt of job cuts. According to the latest state employment figures, there were 487,600 workers in devolved services in the second quarter of 2012, of whom 282,000 were in councils, around 50,000 of them teachers.

Over the past year, overall staff numbers had fallen by 11,400, of which 7000 were in councils.

Since the start of the recession, the overall public-sector head count has fallen by 37,800, or 7.2%, but in local government the drop has been 31,700 posts, or 10.1%.

John McLaren, an economist with the Centre for Public Policy for Regions at the University of Glasgow, said continuing Westminster cuts mean wage restraint will be needed for some years to come.

"Whether 1% is enough to satisfy public-sector staff is a matter for conjecture at this stage. However, if more is found then which budgets will suffer as a result?"

A Cosla source said money would stay tight next year, and suggested any increase would need to be tied to workplace concessions.

"We would be struggling to go anywhere higher than 1%, which will not satisfy the trade unions. We would also need to consider what we would ask for in return," the source added.