Prime Minister David Cameron on Wednesday condemned planned public sector strikes over pensions next week as irresponsible but appeared resigned to them going ahead.

More than two million workers could strike on November 30 in what unions say would be Britain's biggest industrial action in a generation. Members of some 30 public service unions backed the stoppage over plans to make them pay more and work longer for their pensions.

The strikes could shut schools across the country, leaving many parents having to stay at home and disrupting business. Cameron said parents should be allowed to take children to work where it was safe.

The timing is embarrassing for the coalition, coming just a day after the government publishes its autumn financial statement which is expected to show that growth is undershooting forecasts.

It really is irresponsible when negotiations are ongoing to cause strikes that will lead to the closure of most of the classrooms in our country, he told parliament.

It is the height of irresponsibility. What is on offer is an extremely reasonable deal.

His comments amplified an article he wrote in the Sun on Wednesday, urging workers not to strike and noting low turnout levels in many of the union ballots authorising action.

Frankly, these strikes are going to go ahead. Everyone should be very clear about where responsibility lies, he added.

Some Conservatives want labour laws to be tightened to impose a minimum turnout level for a strike ballot to be valid.

The pension reforms are part of government efforts to cut a budget deficit that peaked at more than 11 percent of national output.

Unison, Britain's biggest public-sector union involved in the dispute, and the powerful Trades Union Congress (TUC), which will coordinate the stoppage, attacked Cameron's remarks as baseless.

Far from being a strike directed by so called 'union barons '.workers voted overwhelmingly, in a democratic ballot, for action over changes to their pensions, a Unison spokeswoman said.

The TUC dismissed Cameron's remarks as hypocritical.

Four unions had more of their members vote for action than Mr Cameron managed to get (in a 2010 parliamentary election) from his ultra-safe constituency's voters, the TUC said in a statement to Reuters.

Even prison officers, who, because of the country's strict labour laws are not allowed to strike, have indicated they may be willing to break the law and support the action.

At the start of the month, after eight months of negotiations, the government offered a revised deal to help resolve the bitter dispute only to be rejected as not far-reaching enough.

Its revised proposal would allow workers to build up their pensions quicker while those within 10 years of retirement would see no change.

(Reporting by Stefano Ambrogi)