The government has warned trade unions the current offer on the table is the best they are ever going to get, as 2.6 million public sector workers prepare to strike in protest at changes to their pension schemes.
Danny Alexander, the chief secretary to the Treasury, told the Guardian it was "utterly bizarre" for the unions to strike while negotiations were ongoing and said he could withdraw the current offer if it is not accepted.
"I reserve the right to take those enhancements off the table if an agreement can't be reached.I don't want to do that. I don't want to be in that position. I want to be in a position where we have got an agreement," he said.
Public sector unions are set to stage the biggest strike in decades on Wednesday in protest at changes to their pension schemes which will see their members having to work longer and contribute more.
David Cameron has branded the strike "irresponsible" and the Treasury has claimed the day of action will cost the economy more than £500m - a figure unions have branded "fantasy economics".
Francis Maude, who has been negotiating with unions alongside Alexander, has also suggested the law could be changed to make it harder for unions to take strike action.
The Cabinet Office minister told the Daily Telegraph that the industrial action was “stupid and wrong”.
“People will look at the offer we have made, look at the pension schemes that public sector staff will still have afterwards. I think people will say, that’s pretty bloody reasonable actually," he told the paper.
Maude said in the wake of the dispute the government may impose a new legal time limit on the mandate unions have to stage strikes after their members vote in favour.
Responding to the comments by Maude and Alexander, Public and Commercial Services union general secretary Mark Serwotka said the ministers were making "wild allegations".
"The latest threats about further curbs on strike laws and offers being withdrawn follow ridiculous claims earlier this week that the strike could cost £500 million and put jobs at risk," he said.
"This just shows how little grip they have on the detailed and very serious issues at stake for millions of public sector workers, and calls into question their competence and suitability for these negotiations.
"Such erratic behaviour and wild allegations are becoming increasingly frequent from ministers who claim negotiations are ongoing even though they say they've made their final offer."
The strike is likely to see whole swathes of the public sector shut down, including nine out of 10 schools.
While passengers at Heathrow face 12-hour long queues when border officials walk out, according to the airport's operator.
BAA has warned the world's busiest airport will be crippled by "gridlock" and that arriving planes may have to be diverted to other countries.
The Home Office plans to staff border controls at airports with non-unionised civil servants from across Whitehall. According to the Guardian the UK Border Agency plans to fly home embassy staff from abroad to man the border.
Immigration minister Damian Green said the strike was "completely unnecessary". He would neither confirm or deny to Sky News that the Army was on standby to help man the border.
"We are determined to keep the border secure, we are appealing to those who are thinking of going on strike to take a look at the offer on the table, it's a fair offer, it protects the lower paid."