Keir Starmer is bracing for a frontbench rebellion amid a crunch vote on a ceasefire in the Israel-Gaza conflict.
It comes as the SNP attempts to use an amendment to the King's Speech to try and force a Commons vote on the issue on Wednesday.
Labour shadow ministers who vote for the ceasefire could be sacked but one frontbencher told The Mirror they were prepared to accept the consequences. They said: "The general sense is we're on the wrong side of history on this one. "Every single NGO is asking for it [a ceasefire]. Do we know better than the NGO's on the ground? The public are on the side of a ceasefire".
Reports have also suggested the Labour leadership believes more than 10 frontbenchers could defy orders and support the ceasefire amendment if it is selected by the Commons Speaker on Wednesday.
It is expected that Labour MPs will be asked to abstain if the motion is picked for a vote. A party spokesman said: "We're not going to be engaging with the party political game-playing by the SNP in Parliament".
Teachers, civil servants and train drivers walk out in biggest strike in decadeThe Middle East conflict has caused splits in the Labour Party, with the leadership backing the Government's position of pushing for humanitarian pauses. It has stopped short of calling for a total cessation of hostilities.
In an attempt to avoid resignations Mr Starmer will also put forward an amendment on behalf of the Labour Party on Wednesday.
A party spokesman said: "Labour's amendment reaffirms the position set out in Keir Starmer's Chatham House speech and reflects our concerns about what we've seen on the ground in the last fortnight, which includes the lack of hostage release, the insufficient amount of aid and utilities getting in and being distributed, the scale of civilian casualties in Gaza and the amount of violence on the West Bank."
Last week the ex-Labour shadow minister Imran Hussain quit the party's top team "with a heavy heart" over its stance on the conflict in the Middle East and dozens of Labour councillors have already resigned.
Speaking on Tuesday the Shadow Chancellor Rachel Reeves refused to be drawn on the possible vote on BBC Radio 4's Today programme - but stressed she was "incredibly concerned about the scenes we're seeing in Gaza, particularly at the hospitals." She urged Israel to "show restraint" to allow essentials into the territory.
The Shadow Foreign Secretary David Lammy also told MPs in the Commons: "Gaza is in a humanitarian catastrophe, more than 1.5 million people have been displaced, there are desperate shortages of basic essentials, does the minister agree that the short pauses in the north are clearly not enough?
"Gazans need aid now, they need medicines now, they need water now, they need food now, they need fuel now, a full comprehensive and immediate humanitarian pause in fighting across the whole of Gaza now to alleviate Palestinian suffering and for Hamas terrorists to release the hostages." Foreign Office minister Andrew Mitchell said: "All deaths of civilians are to be profoundly regretted."