Jeremy Corbyn has insisted he is "ready to reach out" to his enemies in the party but warned he would stand for re-election if they staged a challenge for the top job.
The Labour leader said MPs who have set their face against his tenure must "respect" the views of the members who elected him.
Top priority must be opposing the Conservatives and giving voters a real alternative, he said.
In an article for the Sunday Mirror, he wrote: "I am ready to reach out to Labour MPs who didn't accept my election and oppose my leadership – and work with the whole party to provide the alternative the country needs.
"But they also need to respect the democracy of our party and the views of Labour's membership, which has increased by more than 60,000 in the past week alone.
"Our priority must be to mobilise this incredible force to oppose the Tories, and ensure people in Britain have a real political alternative.
"That is my priority and always will be as leader of our party.
"Those who want to challenge my leadership are free to do so in a democratic contest, in which I will be a candidate."
The plea for calm comes at the end of a tumultuous week that saw most of his front bench team walk out and 172 of his MPs back a motion of no confidence in his leadership.
Mr Corbyn's aides are reportedly keeping Tom Watson away from him, fearing he will try to "bully" the 67-year-old leader into quitting.
The deputy leader has been trying to seek a meeting to find a way of negotiating a settlement as the crisis engulfing the party shows no sign of abating.
Mr Corbyn's team said it had a "duty of care" to the leader and highlighted his age, according to the Observer.
A spokesman for Mr Watson said: "Tom and Jeremy have always had a good working relationship and a friendly personal relationship. They have never even raised their voices to one another."
Mr Corbyn's team said the claims were nonsense from an anonymous source. "Jeremy has met Tom on a couple of occasions this week," a spokesman said.
Angela Eagle, who is tipped as a potential challenger to Mr Corbyn, renewed her call for him to do the "right thing for the party and the country".