Jeremy Corbyn has been warned against carrying out a "punishment" purge of critics from his shadow cabinet amid speculation high-profile figures could be ousted from his top team.
The Labour leader is expected to attempt to bolster his position by moving or sacking key members of the shadow cabinet, but veteran frontbencher Pat McFadden said Mr Corbyn risked looking "petty and divisive" if he carried out his so-called revenge reshuffle.
Shadow cabinet minister Michael Dugher, whose own place is reported to be in jeopardy, warned the leader would end up with a "politburo of seven" at the top of the party if he attempted to surround himself with allies from the Labour left.
Shadow Europe minister Mr McFadden defended his boss, shadow foreign secretary Hilary Benn, whose support for bombing Islamic State (IS) in Syria put him at odds with Mr Corbyn.
Other senior Labour figures thought to be under threat include shadow defence secretary Maria Eagle, who has clashed with the leader over the retention of the Trident nuclear deterrent.
Mr McFadden said: "One thing I would say about ... Hilary Benn and Maria Eagle is there is no question about their competence to be shadow ministers."
He pointed out that the Syria decision was a free vote among Labour MPs and Mr Benn should not pay the price for his views - particularly as Mr Corbyn had a long history of disagreement with Labour leaders.
Mr McFadden told BBC Radio 4's Westminster Hour: "If it's about political disagreement, I think you have to pause here - especially if it's about the Syria vote that took place last month because this was on a one-line whip, it was not on a three-line whip.
"Also if you look at Jeremy Corbyn's own record, his whole career is based on disagreeing with party leaders so I think there is a danger for him in this, in carrying out a reshuffle as a punishment for shadow minister who disagree with him.
"He has talked of an open, pluralist kind of politics but a reshuffle for that reason could end looking more petty and divisive than open and pluralist politics. I think that is a risk for him if he proceeds for that reason."
Mr Dugher, whose job as shadow culture secretary is also viewed as unsafe, also highlighted Mr Corbyn's declarations of support for different points of view to be heard within the party.
The shadow cabinet minister insisted Labour is a "broad church not a religious cult" and warned Mr Corbyn that a big reshuffle would be inconsistent with his calls for open debate in the party.
While a shadow cabinet reshuffle would reduce the risk of the leader and his frontbenchers speaking from opposing positions, it could trigger a wave of resignations.
Sacking Mr Dugher, who also voted for bombing in Syria, could anger his senior allies such as deputy leader Tom Watson and shadow home secretary Andy Burnham.
Mr Dugher told Pienaar's Politics on BBC Radio Five Live: "Reshuffles are a matter for the leadership.
"In my experience having worked closely with previous leaders, there's a reason why they tend to be a bit reluctant to go down the path of big reshuffles and that's because they do try and hold the party together, they do recognise that the Labour Party is a broad church not a religious cult, that you need people of different backgrounds and try and get the best possible talents.
"Ultimately that will be a decision for Jeremy.
"In truth, I don't see it happening and the reason why I don't see it happening is because I think it would be inconsistent with what Jeremy has talked about since he got the leadership, which is about room for a little dissent, about having debates."
Meanwhile, Labour former minister Kim Howells described Mr Corbyn and his team as "superannuated Trotskyite oppositionists" who have brought the party to its knees.
Asked about the state of the party on Pienaar's Politics, he said: "It keeps me awake at night.
"I've never seen the party in such a deplorable state.
"It isn't an opposition - in a democracy you've got to have an opposition and we haven't got one at the moment.
"These are superannuated Trotskyite oppositionists, they are not real politicians and I'm afraid it's a disaster as far as I'm concerned."