Labour MPs have branded a list ranking their loyalty to Jeremy Corbyn "particularly stupid".
The list divides MPs into five categories from "core" to "hostile" and was reportedly drawn up by key allies of the party leader.
Chief whip Rosie Winterton and Sadiq Khan, the party's candidate for mayor of London, are identified as "hostile", according to the document leaked to The Times.
Former Labour leader Ed Miliband, shadow culture secretary Maria Eagle, shadow education secretary Lucy Powell and shadow environment secretary Kerry McCarthy are among those listed as negative.
David Cameron used Prime Minister's Questions as an opportunity to mock the Opposition over the list, telling the Labour leader, "I thought I had problems" and putting himself as a "core" supporter of Mr Corbyn.
Asking MPs to raise their hands if they were core supporters, the premier, along with many of his backbenchers, laughed as they put up their own arms. No Labour MPs put up their hands.
Michael Dugher, who was sacked as shadow culture secretary in Mr Corbyn's reshuffle earlier this year, said: "That 'list' is particularly stupid".
Wes Streeting, who was classed as "neutral but not hostile," said: "Dismayed by this. We're weeks away from elections across country. That should be our focus, especially those at top."
Asked if he was "hostile" to the party leader, a.spokesman for the mayoral candidate said: "No. Sadiq Khan is his own person and is fighting his own campaign to be Mayor of London. Jeremy Corbyn's name is not on the ballot paper."
A shadow minister classed as "negative" told the Press Association: "I have no idea why I'm in that column. Not had any rows with him or his team, my policy brief doesn't bring us into conflict. I just get on with my job. All seems a bit random."
The core group has 19 names listed but they include Mr Corbyn and Michael Meacher, who died last year. Among the other names are shadow chancellor John McDonnell, Clive Lewis, shadow energy minister and Diane Abbott, shadow international development secretary.
Among those in "core group plus" are Emily Thornberry, shadow defence secretary, Keir Starmer, shadow home office minister and shadow energy secretary Lisa Nandy.
Shadow business secretary Angela Eagle and shadow Commons leader Chris Bryant are ranked as "neutral but not hostile".
A spokesman for Mr Corbyn said: "It doesn't come from this office and we have no knowledge of it."
Former frontbencher John Woodcock tweeted that the list made the party a "laughing stock" but later deleted the post.
It said: "F****** disaster. Worse week for Cameron since he came in and that stupid f****** list makes us into a laughing stock."
Mr Woodcock, who was ranked as "hostile", describes himself on Twitter as "increasingly angry with people who think politics a parlour game".
Mr Corbyn's office has attempted to distance the leader from the list.
An email has been sent to MPs which states: "This has nothing to do with Jeremy Corbyn's office and does not reflect his views.
"Jeremy Corbyn supports and works closely with the Chief Whip and the Whips' Office."
One MP told the Press Association: "People are joking is there an appeals procedure because they have been classed as more supportive than they are."
A senior Labour source denied speculation that the list may have been drawn up by Mr Corbyn's political secretary Katy Clark.
"Katy Clark knows resolutely nothing about it and had no involvement in it, and nor did anyone else in the leader's office," said the source.
Asked about Mr Cameron's use of the list to attack Labour at Prime Minister's Questions, the source added: "The reality is that the list has caused some problems, clearly, but it hasn't come from the leadership, it hasn't come from the leader's office and doesn't reflect the views of Jeremy Corbyn.
"Jeremy Corbyn has a good working relationship with the Labour Party and with the shadow cabinet, the chief whip, the Parliamentary Labour Party. There are no lists in the leader's office that categorise MPs and we have no knowledge of its origin.
"The Prime Minister clearly had a lot of activity with it today, but it's got no bearing on reality."
Former shadow cabinet member Rachel Reeves - who was included in the "hostile" category - described the existence of the list as "totally ridiculous and counter-productive".
Ms Reeves told BBC2's Daily Politics: "This week all Labour MPs have been in the chamber, trying to hold the Prime Minister and Osborne to account for these cuts. We've all been working together on that, and a list like this which categorises us in this sort of childish way, I think it is really disappointing.
"I just wish that the leader's office - if it comes from the leader's office - would concentrate on holding the Tories to account, rather than try to divide the Parliamentary Labour Party, which is the only thing that that list does."
Asked whether the Prime Minister kept a similar list, a senior Downing Street source said: "It's a novel experiment that the Labour Party were conducting, a brave decision, but not one I think we will be adopting."
Pat Glass, who was listed in the "core group plus" group, said the list had caused "much hilarity in the tea rooms" but warned it raised trust issues in the party.
The North West Durham MP told BBC Radio 4's World At One programme: "If it is correct then we have some questions to ask about trust within the party where colleagues are being called hostile.
"The most important thing for me was it gave Cameron a shield at PMQs."