Shadow chancellor Ed Balls has urged unions not to fall into a government "trap" by striking over plans to reform public sector pensions.

He said Chancellor George Osborne was "desperate" to provoke industrial action so he could blame them for the weak economic recovery.

Ministers dismissed the suggestion and said negotiations were still ongoing.

But Unison leader Dave Prentis said the government had "scuppered" the talks by appearing unwilling to compromise.

Union leaders are threatening the biggest wave of industrial action since the general strike of 1926, after the government unveiled proposals for public sector employees to work longer and pay more for less generous entitlements in retirement.

The Association of Teachers and Lecturers - one of three unions due to strike on 30 June - has said it will call off the walkout if the government is willing to discuss the level of increases to pension contributions.

'So frustrating'

Mr Balls said the government was deliberately "picking a fight" with the unions.

"George Osborne is desperate to have that confrontation - he's been saying it for months," he told the BBC's Andrew Marr programme.

Analysis Ed Balls is doing two things - criticising the coalition and warning the unions that maybe it is time to tone down the rhetoric. But his words throw Labour's own position into the spotlight. On the airwaves, every shadow minister is being asked whether they support the three unions who are planning to strike over pension reforms on 30 June. Labour could suffer if public opinion sides with the government rather than the unions - who are also the party's biggest financial backers. Ed Miliband is also keen to show he is not in the pockets of union bosses, who helped him win the Labour leadership and earned him the "Red Ed" tag. And now Lord Hutton - the former Labour minister who wrote the report that recommended these reforms - has called on Mr Miliband to make it clear where he stands on pension changes and the strikes they have provoked.

"The trade unions must not walk in to the trap of giving George Osborne the confrontation he wants to divert attention from a failing economy. "

Mr Balls said he would "not condemn strikes that haven't happened yet", and said he did believe unions wanted to have "a proper debate and discussion".

"That's why it's so frustrating to see suddenly the Treasury breaking out of the negotiations and seeming to say, 'We've made decisions'."

Treasury Chief Secretary Danny Alexander said the government was "absolutely not" trying to provoke a battle with unions.

"There is a huge amount of room for dialogue," he told Sky News. "There is a huge amount of detail about public sector pensions that we've been discussing in the talks... and we need to take that forward over the coming months."

He insisted the talks could still be constructive, adding: "I don't think my message is uncompromising at all."

But Mr Prentis said a speech by Mr Alexander on Friday, setting out the government's planned changes to pensions, had effectively rendered the talks meaningless.

"If we go back into negotiations on the basis of dialogue but no changes in the proposals, what's the point in that?" he told the BBC.

"If we can get an assurance that the talks are meaningful.. then obviously we'd continue the talks, but we didn't get that impression on Friday."

Unison, which represents 1.3 million people working for local authorities, the NHS, colleges and the police, has not yet balloted its members on industrial action, but Mr Prentis said that would change if they continued "to be treated with disdain".

"And it will be the biggest action since 1926 because up to 10 million people will be involved."

Job cuts

The PCS union, which represents almost 300,000 civil servants, is one of those set to strike on 30 June, and its leader, Mark Serwotka, told the BBC it was very unlikely that the walkout would be called off.

"The government would have to say that they're prepared to seriously negotiate, that they're not going to tell us in advance that everything is going to be worse, that they're prepared to look in a different direction," he said.

"I think the chances of that between now and 30 June - if I'm honest on a scale of one to 10 - are fewer than one."

Public sector workers are already facing heavy job cuts and a pay freeze.

The government's pension proposals would see employees - bar members of the armed forces, police and fire service - receive their occupational pension at the same time as the state pension in future.

Many can currently receive a full pension at 60 but the state pension age is due to rise to 66 for both men and women by April 2020.

Ministers also want to move the public sector scheme from a final salary system to benefits based on career-average earnings. However, lower paid workers would not have their pension contributions increased.

Lord Hutton, the former Labour minister whose recent report formed the basis of the government's plans, said the taxpayer had long footed the bill for public sector pensions.

"I don't personally believe that ministers want to provoke a confrontation with the trade unions - quite the opposite. I think they're trying to find an agreement," he told BBC1's Politics Show.

He said Ed Miliband should endorse his report, and when asked if he would like to see the Labour leader "stand up and say 'call off the strikes'", he replied "of course".