The number of new civil claims for damages over alleged News of the World phone hacking faced by Rupert Murdoch's News International has reached nearly 50, including Sir John Major's former daughter-in-law Emma Noble, the high court has heard.

Others seeking damages for alleged invasion of privacy from News Group Newspapers, the News International subsidiary that published the now-closed Sunday tabloid, include former Conservative cabinet minister and chief whip Lord Blencathra and former Fire Brigades Union general secretary Andy Gilchrist.

At a case management conference at the high court in London on Friday, Hugh Tomlinson, QC, representing victims of alleged phone hacking, told Mr Justice Vos that he had 44 new cases filed while two others had submitted their claims via another legal representative.

It is expected that up to 200 new claims will be filed over the coming months, Tomlinson told the court in a previous hearing.

The cases are part of a second wave of civil actions which Vos is managing following the settlement of more than 50 cases earlier this year including claims by Jude Law, Charlotte Church and Lord Prescott.

Tomlinson did not disclose the names of the claimants, but court papers show that new cases submitted to the high court in the past week include claims by Noble, the model and actor who was married to Major's son James for five years up to 2004.

Tomlinson told the court that News International had received 100 requests for discovery of preliminary disclosure.

He said there were 4,791 potential phone-hacking victims, of which 1,892 had been contacted by the police. The police believed 1,174 were "likely victims".

Court 30 in the Rolls Building of the high court was packed, with more than 50 law firms acting for victims.

Vos said there were 58 firms of solicitors representing only 100 victims, which he told Tomlinson was "unbelievable".

The judge added that he wanted to ensure costs are reduced for claimants. "Many of them have seen the light and have instructed lawyers who have specialist knowledge of this case," said Vos.

He suggested possible tariffs of costs for each element of the legal action. This would mean fresh claimants could access to information relating to the News of the World's phone-hacking activity already produced on discovery in earlier cases, without incurring the costs associated with a full action. "I will have no sympathy for outrageous cost estimates," he said.

Public figures including Cherie Blair, the wife of the former Labour prime minister, Alex Best, the wife of the ex-Manchester United footballer George Best, have already filed lawsuits, and the man wrongly accused of murdering Rachel Nickell, Colin Stagg.

Others who have filed claims include comedian Bobby Davro, actor Tina Hobley's former husband Steve Wallington, TV personalities Jamie Theakston and Jeff Brazier, former boxer Chris Eubank, and footballers Peter Crouch, Kieron Dyer and Jermaine Jenas.

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• This article was amended on 23 April 2012. The original said that actor Tina Hobley was among those who had filed a claim for damages. This has been corrected.