The public sector pensions strike next week could cost the economy half a billion pounds and lead to job losses, the Government has said.
The planned walkout on November 30 by over two million workers will lower output in the public and private sectors, said the Treasury.
Ministers said the biggest impact will be caused by thousands of school closures, forcing parents to work from home, make childcare arrangements, or take their children to the office.
Chief Secretary to the Treasury Danny Alexander told a press briefing there was "no more money on the table" to settle the bitter row over the Government's controversial pension reforms.
Mr Alexander said he might take his daughter to work with him next week as her school will be closed by the strike.
Cabinet Office minister Francis Maude said there was a correlation between economic output and employment. He added: "Exactly what that relationship is is very hard to anticipate but if we lose a big chunk of output it is hard to see how that does not translate into fewer jobs."
Government sources said contingency plans were being made to deal with the strike, including the impact at ports and airports. It has emerged that civil servants have been asked to volunteer by the Border Agency to cover for striking staff next week.
Mr Maude said it was difficult to predict the impact of the strike, but the cost to the economy was based on the expectation that two-thirds of schools will close.
"There will be a massive impact on schools, which has the biggest knock-on effect on the economy. We are confident that emergency care in the NHS will be maintained, but there will be people whose operations are delayed. That is a very great tragedy. We will do everything we can to prevent the strike having a real impact on people's lives."
Mr Alexander said the Government had made a "significantly improved" offer which gave millions of workers the promise of a good pension.
© 2011 Press Association