The Prime Minister has ordered an investigation into whether the North Wales child abuse inquiry 'properly did its job' following fresh allegations.
The independent investigation will look at whether the Waterhouse Inquiry, held 12 years ago into abuse at the Bryn Estyn children's home in the 1970s and 1980s, was "properly constituted".
The Children's Commissioner for Wales has also backed calls for the new inquiry to take place.
Keith Towler insisted concerns about a cover-up by powerful people were "understandable" and a full investigation was the only way to resolve the issue.
The intervention came after a victim of the North Wales care home scandal criticised the way the original Waterhouse Inquiry was conducted.
The tribunal, led by Sir Ronald Waterhouse, heard evidence from more than 650 individuals who had been in some 40 homes between 1974 and 1990, publishing its report in 2000.
But in a recent interview with the BBC's Newsnight, Steve Messham said the terms of reference meant he was not able to raise the alleged abuse that took place outside the care system.
The Secretary of State for Wales David Jones will meet Mr Steve Messham to discuss the concerns he raised in the Newsnight programme.
Speaking in Abu Dhabi, Mr Cameron said: "These actions are truly dreadful and they musn't be left hanging in the air. So I am taking action today, first of all to make sure that Mr Messham can meet urgently with the Secretary of State for Wales so he he can hear his allegations and his points directly.
"Secondly, I am going to be asking a senior independent figure to lead an urgent investigation into whether the original inquiry was properly constituted and properly did its job and to report urgently to the Government.
"But third, I would also urge anyone who knows anything about these matters to go to the police. That is where evidence should be taken so that action can be taken and we can deal with this dreadful, dreadful issue.