Unions representing workers across the health service have warned they could stage coordinated industrial action if agreement cannot be reached on the future of the NHS pension scheme.

The Royal College of Nursing, the British Medical Association and Mangers in Partnership last week signed up to the multi-union Pension Campaign Group, along with Unite, Unison and GMB.

Following a summit, 12 unions issued a statement saying they remained “committed” to pension negotiations with the government but they warned ministers not to “set out unrealistic timetables or ultimatums”.

Ministers have proposed increasing NHS pension contributions by an average of 3.2 per cent over three years, starting in 2012. Although full time staff earning less than £15,000 would see no increase, employees earning more than £48,983 and £110,000 would see increases of between about 5 per cent and 6 per cent respectively.

The government has set a deadline of the end of October for concluding negotiations. Unions claim this is unrealistic and fear it indicates unwillingness to compromise.

Unions also argue it is impossible for their members to make a judgement about whether to accept the government’s proposal without knowing the outcome of a separate, ongoing consultation on the retirement age and future structure of pension schemes.

MiP chief executive Jon Restell said: “Pensions is one of the most complex discussions you can ever have. The risk of making a long term mistake is huge. We don’t want to keep hearing about the end of October deadline.”

Initially the campaign will focus on winning the public argument. Unions will also consider how patients can be protected in the event of any industrial action.

Mr Restell added: “Whatever form [industrial action] takes it will not be a one off, one day event – that won’t change the government’s position. If people are serious about using industrial action then they will have to see it as something that might run for weeks and months.”

NHS Employers director Dean Royles said talk of industrial action was “premature”. He urged staff to engage in the discussions over the future of the pension scheme.

A Department of Health spokesman said the NHS pension would remain “one of the best available” and promised none of the rights employees had accrued would be affected.

But he added: “The status quo is not sustainable with people living much longer, substantially increasing the cost to the taxpayer.”