Speaking on a visit to Leeds, International Trade Secretary Liz Truss called on Labour to back the Prime Minister's motion for a pre-Christmas election in the Commons on Monday.
Mr Johnson told Labour leader Jeremy Corbyn to "man up" and support his call for a December 12 poll, which he was offering in return for giving MPs more time to scrutinise his Brexit deal.
The PM's official spokesman played down suggestions made the previous day by Number 10 that other government business would be reduced to a "bare minimum" if it was defeated on Monday.
But Mrs Truss, who was in Yorkshire for talks with local businesses about export opportunities post-Brexit, said: "We need to get Brexit sorted out. It is creating a limbo, businesses are holding on investment until they know what's going to happen, we need to get this sorted out.
"The Labour Party have to understand, this isn't just about their party political interest, this is in the national interest that they need to support this deal.
"What is happening in Parliament is the Labour Party are trying to frustrate everything we're trying to do. We don't have a majority to get things through.
"Of course we will continue to work night and day, I will continue to work as International Trade secretary to support businesses to get their exports into other countries to break down barriers that might be preventing that business, to attract investment here in Britain.
"I'm not going to be working half hours or anything, I'm going to continue to be travelling around the country and the world, making the case for Great British exports, but in Parliament it is very, very difficult for the Government to make any progress on our priorities, because we've got an opposition who are blocking everything.
"That's that's the reality of what we face, which is why we need a General Election."
During her visit to Yorkshire, Mrs Truss, who was educated at Roundhay School in Leeds, the Conservative visited air conditioning manufacturer Airedale International in Rawdon and the Emmerdale Studio Experience on Kirkstall Road.
'Take no deal off the table and we'll back an election'
Speaking in Milton Keynes, Mr Johnson said it was up to Mr Corbyn to decide whether to get the deal done.
The PM insisted Britain could still leave the EU on October 31 - despite the EU 27 accepting the "principle of an extension" - but said the fate of Britain's exit date was now in Brussels' hands.
Labour - whose votes will be needed if the PM is to get the two-thirds majority in the Commons which he requires to go to the country - has said it will only back the plan if Mr Johnson makes "absolutely clear" no deal is off the table and a January extension is granted.
"I've said all along - take no deal off the table, and we'll have the election," Mr Corbyn told ITV's This Morning.
But there are concerns in Whitehall that if ministers cannot get the Withdrawal Agreement Bill through now, they will be facing the prospect of yet another extension beyond January 31, with the possibility MPs could again take control of the Commons timetable to pass a "Benn Act 2".
Following the meeting of EU ambassadors today, the European Commission's chief spokeswoman Mina Andreeva told a Brussels press briefing: "The EU 27 have agreed to the principle of an extension and work will now continue in the coming days."
She said their intention was to take the decision by a written procedure, reducing the likelihood of an emergency EU summit next week - just days before Britain is currently due to leave.
An EU source said the ambassadors' meeting was constructive and there was "full agreement" on the need for an extension.
They are expected to meet again on Monday or Tuesday to finalise an agreement.
The Prime Minister was forced by Parliament to write to Brussels requesting the delay after failing to win approval for his deal at last weekend's special Saturday sitting.
However, many MPs say his proposed election timetable - which would require them to complete the ratification of his deal by November 6 when Parliament would be dissolved - still does not allow time for proper scrutiny.