Jeremy Corbyn has urged his MPs to unite behind him if, as it is expected, he is voted party leader again with an even bigger mandate from members.
The veteran MP is the overwhelming favourite to see off Owen Smith's challenge when the results of the leadership election are announced in Liverpool just before noon.
The left-winger received support from senior shadow cabinet member Andy Burnham, who remained neutral during the contest.
Mr Burnham said Mr Corbyn would have earned the right to lead the party "without interruptions, noises off and undermining".
The shadow home secretary said Labour MPs had treated Mr Corbyn badly when he became leader last year and should now be prepared to serve on his front bench in the "right spirit".
He told the Guardian: "I've never seen in 15 years a Labour leader treated like that; it was disrespectful."
But Lisa Nandy, who quit the shadow cabinet following the EU referendum vote, said there would have to be a change of culture if he is to reunite the party.
A political party, a social movement, a shadow cabinet simply cannot survive if you refuse to hear dissenting voices and work as a team to try and resolve differences," she told BBC2's Newsnight.
In a video message, Mr Corbyn insisted that critics have a "duty to unite", regardless of who wins and how big the victory is.
Mr Corbyn insisted that the enthusiasm triggered by the second leadership campaign would boost the party's chances in the next general election in 2020.
With membership numbers at more than half a million and 40,000 volunteers signing up to take part in his campaign, Mr Corbyn said Labour would deliver a "new kind" of general election campaign.
He said it would be "the biggest, best and most visible we have ever run".
"Now let's turn our agreement into unity, our passion into action and our ideas into reality," he said.
"We must win the next general election so Labour can rebuild and transform Britain so no one and no community is left behind. We can and must do that together."