Tory and Labour members of the culture select committee are at odds over how far to criticise the Murdoch family barely 24 hours before publishing a report on phone hacking and News International.

The 11 members of the committee are set to vote on several of the most disputed issues at a meeting today in an attempt to forge some sort of consensus ahead of publication tomorrow.

But the group has been deeply divided in discussions, with Labour MPs such as party vice-chairman Tom Watson keen for a more scathing judgment on James Murdoch, in particular. Mr Murdoch was called in front of the committee on July 19 and recalled on November 10.

During his second appearance, when he repeatedly denied being aware of wrongdoing within the company, Mr Watson told Mr Murdoch: “You must be the first mafia boss in history who didn’t know he was running a criminal enterprise.”

Mr Murdoch, deputy chief operating officer at News Corp, blamed Tom Crone, former legal affairs manager at News of the World, and Colin Myler, former editor of the paper, for failing to tell him about evidence showing illegal phone-hacking was widespread at the Sunday newspaper.

He repeatedly said he had been unaware of the contents of a crucial email that led to huge payouts to victims of hacking – a claim that was swiftly disputed by both former colleagues. In the private committee discussions, some of the Tory members have been more forgiving of Mr Murdoch than their Labour counterparts, insisting that his version of events is feasible.

Those party divisions worsened last week, with some Labour MPs privately critical of John Whittingdale, committee chairman, for making comments supportive of Jeremy Hunt, culture secretary, over his handling of the News Corp bid for BSkyB.

With five Labour MPs and five Tories on the committee, the casting vote could end up with Adrian Sanders, a mild-mannered Devon MP who is its only Liberal Democrat.

In early April, when James Murdoch resigned as chairman of BSkyB, some pundits speculated that this was somehow connected to the imminent report from the committee. Mr Murdoch, however, merely said he wanted to distance the company from events at News International, saying he was “determined that the interests of BSkyB should not be undermined by matters outside the scope of the company”.

The report, which has been delayed for four months, will criticise other senior News International figures, including Rupert Murdoch.

The document will be published overnight – to prevent the full contents leaking – and not released until 10.30am on Tuesday, with a lock-in for journalists ahead of a 11.30am press conference.

It is unlikely to refer to either Rebekah Brooks, former chief executive of News International, or Andy Coulson, former editor of News of the World. Both have been arrested by police but have denied any knowledge of widespread phone-hacking at the company.

The report will criticise both Mr Crone and Mr Myler for misleading evidence given to parliament three years ago. Mr Myler, former editor of the News of the World, and Mr Crone, the newspaper’s former legal manager, will be accused of failing to disclose their awareness of the full extent of phone-hacking at the paper when appearing at the culture select committee in 2009.

Members, whose meetings have been attended by a parliamentary lawyer, had wanted to publish their report before Christmas but have waited for the