Jeremy Corbyn will say the issue of whether Brexit happens has been “settled” as he formally launches his party’s general election campaign.
The Labour leader will promise to protect “Britain’s vital industries” after the UK has left the EU.
He will tell supporters in Manchester they have “four weeks to transform Britain”.
Mr Corbyn will be joined at the campaign launch by Labour’s new Greater Manchester Mayor Andy Burnham.
Another Labour mayor, London’s Sadiq Khan, has said people are “unclear” about the party’s position on Brexit, and Labour faces the challenge of trying to appeal to both sides of last year’s EU referendum debate.
Prime Minister Theresa May has attempted to portray the 8 June general election as being about Brexit, urging voters to strengthen her negotiating hand.
Labour has already set out six tests, including retaining the same benefits the UK currently has from the single market.
Speaking at his campaign launch in Manchester, Mr Corbyn will say: “This election isn’t about Brexit itself. That issue has been settled. The question now is what sort of Brexit do we want – and what sort of country do we want Britain to be after Brexit?
“Labour wants a jobs-first Brexit, a Brexit that safeguards the future of Britain’s vital industries, a Brexit that paves the way to a genuinely fairer society and an upgraded economy.”
Mr Corbyn has so far steered away from Mrs May’s focus on forthcoming EU negotiations towards Tory cuts to public services and his own party’s spending plans.
But he will accuse the Conservatives of putting party interests above the “real national interest”.
This is after Mrs May claimed Brussels leaked details of a meeting she had with European Commission President Jean Claude-Juncker to try to influence the election.
The pair reportedly clashed over Mrs May’s desire to make Brexit “a success” and whether the issue of protecting the rights of expat UK and EU nationals could be agreed as early as June.
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BBC political correspondent Iain Watson says Mr Corbyn has been accused even by some of his own MPs of trying to ignore Brexit, so now he will be unequivocal.
Mr Corbyn will also claim that “the tax cheats, the press barons, the greedy bankers” would celebrate a Conservative victory, adding: “We have four weeks to ruin their party.
Meanwhile, the Liberal Democrats are claiming that Brexit has put an additional five pence on the price of a litre of petrol.
Nick Clegg, the party’s spokesman on Europe, said motorists were paying the price for a fall in the value of the pound.