About a quarter of a million British civil servants will strike on the day finance minister George Osborne delivers his budget statement this month, heralding the start of three months of protest at austerity measures, their union said on Wednesday.

The Public and Commercial Services union, one of the most militant in Britain which represents state workers from border staff to court employees and tax officials, said it would hold a national walkout on March 20.

It promised there would be further strikes and other forms of disruptive industrial action over cuts to pay, pensions and working conditions.

"This is not a one-day protest. This is the start of a rolling program of walkouts and disruptive action to put pressure on a government that is refusing to talk to us," said PCS general secretary Mark Serwotka.

"We warned more than two years ago that austerity wouldn't work and we were right."

The union says the Conservative-led coalition's economic plans are not working but causing misery for workers.

The strike is timed to coincide with Osborne's budget in which he will outline his agenda for igniting a stagnant economy teetering on the brink of a third recession within four years.

The PCS and other unions have staged a number of strikes in the last two years, mainly over the coalition government's decision to reform public sector pensions.

The action included a walkout by about 1.5 million workers in November 2011, the biggest seen in Britain for a generation.

The government, trying to cut a record budget deficit, says reform is needed as people are living longer and public service pensions are unaffordable. It has also instigated a two-year pay freeze across the public sector which is says has helped to protect jobs.

"It is disappointing that yet again the PCS insist on pushing for futile action which benefits no one, and damages the services they deliver to the public," a Cabinet Office spokesman said in a statement.

Ministers say previous strikes have not been well-supported. The PCS said 61 percent of its members had backed the latest action, although the turnout in the ballot on whether to go on strike was only 28 percent.

Last August, the union called off a planned strike on the eve of the London Olympic Games amid widespread public criticism. Many feared any induistrial action by immigration officials would cause chaos at airports for thousands of visitors attending to the showpiece sporting event.