Up to 30 hospitals are now under investigation as part of the inquiry into Jimmy Savile's alleged abuse of patients at NHS hospitals, the BBC understands.
Inquiries had originally just focused on Broadmoor and Stoke Mandeville and Leeds General Infirmary, with a further 10 trusts added in January.
A final report will be published in 2014.
The late DJ is believed to have abused hundreds of victims.
The former BBC presenter of Top Of The Pops and Jim'll Fix It, who also worked as a Radio 1 DJ and received a knighthood in 1990, died aged 84 in October 2011 - a year before the allegations were broadcast in an ITV documentary.
Revelations that Savile had sexually abused children prompted hundreds of victims to come forward, including those who said they were attacked on BBC premises and at a number of other institutions.
Savile had a bedroom at Stoke Mandeville Hospital, an office and living quarters at Broadmoor, and widespread access to Leeds General Infirmary.
The Department of Health investigation into the three hospitals is being overseen by barrister - and former deputy chairman of the Financial Ombudsman Service - Kate Lampard.
In a written ministerial statement on Monday, Health Secretary Jeremy Hunt said: "The Metropolitan Police Service, working with Kate Lampard, has established there was further relevant information regarding Jimmy Savile.
"The Department of Health asked the Metropolitan Police Service, through an agreed information sharing process, to review information it held to ascertain if it included material related to health and care settings."
He added that it was "vital" that the final NHS investigation report was "thorough and complete and reflected all the evidence about Jimmy Savile's pattern of offending".
The Department of Health said: "The Metropolitan Police Service is still reviewing relevant information. It is not yet possible to be sure how many further investigations may need to take place."
But Liz Dux, an abuse lawyer who represents more than 70 of the claimants, told the BBC she was worried the extension would prolong the distress of her clients.
"These hospitals were known about - all my clients gave their evidence some time ago to the NHS investigation.
"These victims want the investigation concluded, naturally as efficiently as possible, but they want it over, they need closure," she said.
'Further relevant information'
The revelations about Savile have led to a number of inquiries.
Firstly, the police investigation, Operation Yewtree, which has three strands.
One looking specifically at the actions of Savile is due to report in the new year. The BBC understands it will put the number of alleged victims at over 500.
The second strand concerns allegations against "Savile and others".
The third relates to complaints against other people unconnected to the Savile investigations, made by people who came forward after widespread coverage of the scandal.
The BBC has also launched three reviews, including the Pollard Review, which has already reported the findings of its investigation into the dropping of a Newsnight report into claims Savile was a paedophile; and a review by Dame Janet Smith into culture and practices during Savile's career and current policies.
The director of public prosecutions is also reviewing decisions not to prosecute Savile in 2009.