Labor must give priority to restoring Brexit through another referendum, over winning power in a general election, its deputy leader Tom Watson has to say.
He will warn that early elections before the end of the year may fail to resolve the current deadlock.
Going against Jeremy Corbin, he will say that "there is no such thing as a good deal for Brexit" and Labor must unambiguously campaign to stay.
Mr Corbin said he must offer voters both the 'Leave' and 'Stay' options.
Following meetings with union leaders on Tuesday, Labor leader pledged an additional referendum on Brexit with a "credible exit option" against staying if his party wins the next general election.
The choice of manifesto promises to better the Brexit Deal, but is not expected to commit to either leaving or staying.
Mark Servotka, Secretary General of the PCS Union, stated that this was a "common sense" position and the binary choice of a referendum offer was a "huge gamble" that risked "continuing" existing political divisions.
"I think Tom Watson's intervention is irresponsible, not what the label community needs," he told BBC Newsnight.
Mr Watson and other senior Labor representatives, including Brexit shadow secretary Sir Cyrus Starmer, say they will launch a campaign to stay in the EU under all circumstances.
BBC Newsnight political editor Nick Watt says he believes Mr Corbin's goal is to "provide a home" for both the Leave supporters and the "Stay" supporters in the next election, but he may be forced to allow colleagues to campaign on both sides in the event of another referendum.
The label votes twice against Boris Johnson's plans for a poll on October 1
Party leadership insists it is impatient for elections after the risk of fruitless Brexit on October 31 was ruled out.
- The Labor hunt for Brexit reconciliation
In a speech in London, Mr Watson will say that while the autumn general elections seem inevitable given the loss of Boris Johnson's control in Parliament, "which does not make it desirable ".
"Elections should never be single-issue campaigns," he will say, posing vital questions as the future of the NHS, economic inequality and crime will be "drowned" by Prime Minister Boris Johnson's message "made or died." Brexit.
"The only way to end the Brexit impasse once and for all is through a public referendum vote," he will say. "General elections may fail to resolve this Brexit chaos."
In the case of other general elections in the coming months, Mr. Watson says Labor must be "crystal clear" about where Brexit stands, if he wants a hearing for the rest of the domestic policy agenda.
"There's no such thing as a good deal on Brexit, which is why I think we should stand up for it.
"" This is the overwhelming majority of Labor Party members, MPs and unions believe. "
" Come back "
The Liberal Democrats, who pushed Labor to a third place in the European elections in May with a stern anti-Brexit message, urged Brexit to halt its tracks by repealing Article 50 – the legal process for leaving the United
While continuing to call for it, Mr. Watson will say that it is not too late to work to "win back" Lib Dems voters remain if she campaigns "unequivocally".
" My experience on the threshold tells me that most of those who left us because of our politics for Brexit, they did it with deep regret and would very much prefer to come back, "he adds.
" They just want us to make it clear that whatever happens, we will struggle to stay and sound like we are we mean it. "
Mr Watson will say that although 'very difficult', he and many others 'have long respected the outcome of the 2016 referendum.'"  "But in the end, there is a moment," he added. "When the circumstances are so changed, when so much new information comes out that we didn't have in 2016, when so many people feel different than how they felt then, that you have to say, no … the only one the right way to deal with such circumstances is to consult people again. "
In a speech by Congress of the trade union on tuesday, sir cyr starmer will say that another referendum is the only way to "clean up the mess left by the tories".
"And – of course – 'stay' should and will be on the ballot, along with a credible option to leave."
Conservatives stated that Mr Watson had made it clear that he wanted to 'cancel' Brexit 2016 Result of referendum.
"Only Boris Johnson and the Conservatives will deliver Brexit by October 31, with no asses or asses, so we can go on and focus on issues that matter to people," said his party chairman James Cleverly.