Home Secretary Theresa May has announced a new police inquiry into allegations of child abuse in north Wales in the 1970s and 1980s.
Mrs May said the head of the National Crime Agency would lead the inquiry.
Separately, Mrs Justice Macur will investigate the terms of the Waterhouse abuse inquiry, which began in 1996.
Meanwhile, the Conservative party has confirmed it is investigating reports linking one of Margaret Thatcher's former close aides to the allegations.
The alleged abuse centring on children's homes in north Wales - and specifically the Bryn Estyn home at Wrexham - began to emerge in the 1990s.
They were highlighted again last week when victim Steve Messham said the Waterhouse inquiry had uncovered only a fraction of the abuse.
"In the home it was the standard abuse which was violent and sexual. Outside it was like you were sold," he told BBC Newsnight last week, and detailed being tied down and raped in a hotel room.
The crime agency head, Keith Bristow, will look at how the historic claims were handled, and at fresh allegations. He will report by April 2013, Mrs May told MPs.
The Serious and Organised Crime Agency and the Child Exploitation and Online Protection Centre will also be involved.
On Tuesday evening Channel 4 News broadcast an allegation from an unnamed former resident of Bryn Estyn, that he had seen the late Sir Peter Morrison - a former aide to Conservative prime minister Margaret Thatcher - visit the care home and drive away with one of the boys living there.
A spokesman for Conservative Central Office later responded by saying: "we will do everything in our power to ensure these serious allegations are investigated fully." Sir Peter, who was MP for Chester from 1974 to 1992, died in 1995.
North Wales Police Chief Constable Mark Polin said: "Victims and members of the public can be assured that any new identified lines of enquiry will be pursued as rigorously and as swiftly as possible."
But shadow home secretary Yvette Cooper expressed concern about the number of different investigations into child abuse allegations, saying that they would not be able to draw their findings together.
And Tim Loughton, Conservative MP and former children's minister, called for the government to hold one inquiry to cover the different investigations and inquiries currently ongoing into child abuse.
"We have just got to have one, overarching, robust inquiry, led by a high-level figure, looking into all these different stories, to put the whole thing into proper context."
'What was covered up'
In a statement to MPs, Mrs May said: "The government is treating these allegations with the utmost seriousness.
"Child abuse is a hateful, abhorrent and disgusting crime, and we must not allow these allegations to go unanswered, and I therefore urge anybody who has information relating to these allegations to go to the police."
Mr Messham said after a meeting with Welsh Secretary David Jones: "I certainly have confidence that they are taking it seriously... but I haven't got confidence that it's going to be done properly yet. When the inquiry was announced that was a Tory government - we're back to a Tory government. Let's see how it goes."
Mr Jones said that the inquiry "must go wherever it leads", adding that it was "absolutely essential" that abuse victims "should feel that they have had justice".
Wales First Minister Carwyn Jones confirmed that Wales children's commissioner Keith Towler was "actively dealing with a number of people who have contacted him since the weekend".
Wider abuse claims
North Wales Police did investigate the care home abuse claims in 1991. Of eight prosecutions, seven former care workers were convicted. But it was widely believed that the abuse was on a far greater scale, prompting the setting up of a public inquiry in 1996 to look again at the abuse claims.
Headed by Sir Ronald Waterhouse, the inquiry heard evidence from 650 people.
After the report was published in 2000, there were 140 compensation claims settled on behalf of the victims, and numerous recommendations about children in care homes.
However, concerns have now been raised that the remit of the inquiry was too narrow, and that it failed to consider allegations about children being taken out of the homes to be made available to abusers.
Richard Scorer, a solicitor who represented 30 victims at the Waterhouse Inquiry, said the previous inquiry had done a "thorough job" of looking into "what it set out to investigate".
"It could not and did not look into broader paedophile networks. That is not what it was primarily set up to do," he said.
One victim, Martin Watkinson, said what was "finally" needed was "justice for the victims, and prison sentences for the people who were abusing."
The latest abuse inquiries come in the midst of several inquiries into separate allegations of widespread abuse by former BBC presenter Jimmy Savile, relating to hundreds of victims over many decades.
Mrs May told MPs that Her Majesty's Inspectorate of Constabulary was looking at all forces that received allegations in relation to Savile. It would examine whether these allegations were investigated properly, and identify wider lessons from the response of the police forces involved.
She also said that: "If, at the end of the processes that we've set in train, it appears that it is necessary to move forward to a wider investigation then we will look at that."
Correction 10 November 2012: The BBC has apologised unreservedly for broadcasting a report on Newsnight on 2 November over allegations of child abuse which transpired to have involved a case of mistaken identity. As a result the video of the original report has been removed from the website. More details can be found here.