The “time has passed” for Labour to be able to get its own Brexit deal and any agreement should go to a vote, shadow cabinet minister Andrew Gwynne says.
He said the party “will do everything we can to stop no deal”.
But Caroline Flint, one of 26 Labour MPs who have urged Jeremy Corbyn not to call for a second referendum, said she would prefer no deal to no Brexit.
She said the number of Labour MPs prepared to back the government’s Brexit deal “will go up” in the future.
Labour had promised another Brexit vote in certain circumstances, specifically if it could not get its own deal with the EU passed by MPs or if there was no general election.