A £45 billion black hole in Labour's financial plans will detonate a tax and debt "bombshell" if the party takes power, the Tories have claimed.
Chancellor Philip Hammond and Brexit Secretary David Davis will attempt to drive the election battle on to the economy at a joint campaign event on Wednesday.
It comes as the Conservatives launch an attack poster showing Labour leader Jeremy Corbyn and a bomb behind his head with the slogan: "Corbyn: No Bombs for our Army, One big bombshell for your family."
Mr Davis said: "Jeremy Corbyn's nonsensical and irresponsible ideas pose a grave risk to the future of Britain's economy and the finances of every family in the country.
"His many, ill-thought-through promises simply don't stack up and could not be paid for.
"The damage this bombshell would do to the country's finances if Corbyn's coalition of chaos were given the keys to Downing Street would be disastrous."
The Conservatives issued a dossier claiming that the financial "black hole" would be apparent midway through the next parliament in 2019-2020 if Labour stuck to its tax and spending commitments, and pledges to reverse Tory welfare changes.
The tactic of using hard-hitting attack posters against Labour over the economy has worked for the Conservatives in the past, most notably in 1992 when a picture of two giant boxing gloves ran with the slogan: "Labour's Double Whammy. 1. More Taxes. 2. Higher Prices."
A Labour Party spokesman said: "This is yet more nonsense from a Tory campaign that's all slogan and no substance.
"It's the latest desperate attempt to distance themselves from their failures and to distract from the fact that they've not ruled out hitting those on lower and middle incomes with further tax increases.
"Their false claims about Labour's plans in this campaign haven't been worth the paper they've been printed on; they've fallen apart before the ink has dried on their latest press release.
"This will no doubt be no different with more claims that can't be backed up and misrepresentations of the truth. Labour's policies are fully costed and properly paid for."
Labour sought to shift the campaign focus to health by saying it would halt closures of A and E departments in English hospitals if it won the election.
Shadow health secretary Jonathan Ashworth said he would launch a full-scale review of such proposals and stop the Sustainability and Transformation Plan (STP) programme if Labour takes power in June.
He said: "Labour will put the best interests of patients at the heart of our NHS, so I'm announcing we will halt planned closures to hospitals and other services. We will have a moratorium on the STPs.
"We have listened to the hundreds of patients and campaigners up and down the country that have been pleading with the Government to hear their concerns about their local services.
"Threats of hospitals being closed, A and E services moved miles up the road, and children's wards being shut, have caused widespread concern and confusion."
However, Brexit was likely to feature in the election again as European Commission Brexit negotiator Michel Barnier gives a press conference Wednesday, following claims that Prime Minister Theresa May had a tense meeting with European Commission president Jean-Claude Juncker last week.
Responding to a report in the Financial Times that the EU could demand the UK pays an exit bill of up to 100 billion euro, Liberal Democrat leader Tim Farron said: "The proposed cost of our EU divorce bill has almost doubled since Theresa May's disastrous dinner last week.
"This is on top of the £59 billion hole in the public finances that will be caused by Brexit over the next five years.
"Every time the Prime Minister meets with our EU partners, their position hardens and the terms of Brexit seem to get worse.
"This government has chosen the most divisive and damaging form of Brexit, outside the single market, meaning fewer jobs and less money for public services."
The Lib Dems also said Ukip was planning to cut foreign aid from the current 0.7% of GDP to 0.2%.
Lib Dem foreign affairs spokesman Tom Brake said: "Ukip would cheerfully see a child starve to death if it won them some cheap, snarling clip on the evening news."
The PM is to visit the Queen at Buckingham Palace on Wednesday to mark the dissolution of Parliament for the General Election.