Dublin is calling for the case to be re-opened saying it has new evidence about the 1989 murder.

Mr Finucane's death has remained a subject of controversy for the last decade as allegations have been made in that the security forces were involved in the killing.

No-one has been convicted for the crime.

Responding to the latest move, Northern Ireland Secretary Mo Mowlam pledged to bring the lawyer's killers to justice.

Mr Finucane became a target for loyalist terrorists after managing to secure the acquittal of many high-profile republicans.

The Irish Government has passed on documents to London.

According to the Independent a leaked copy of an Irish government document says the papers include evidence to back "widespread suspicions that elements in the security forces were used, at the expense of the rule of law, to prosecute a campaign against those deemed enemies of the state and conceal what that entailed and who was culpable".

'No options excluded'

Responding to the reports, Dr Mowlam said: "I take the situation very, very seriously. I am determined that no option will be excluded."

She said she hoped the new investigation into the killing launched last week by Deputy Metropolitan Police Commissioner John Stevens would result in a prosecution.

"If there is a chance of a prosecution, I am going to see it, and see that the findings of the Stevens [investigation] go to the DPP.

"I am not going to let this drop. If I can get a prosecution I'm not going to lose it just because of pressure," she said.

Calls for an independent inquiry into claims of collusion have been gaining pace since reports by the United Nations and British-Irish Rights Watch outlined new evidence earlier this year.

Calls hard to ignore

Param Cumaraswamy: It's going to be difficult for the UK to refuse a judicial enquiry

Speaking to the BBC, the UN's Special Rapporteur on the independence of judges and lawyers, Param Cumaraswamy, said he believed it was going to be difficult for the UK Government to refuse calls for a judicial inquiry.

He said the murder should be fully investigated by an independent inquiry to see if the security forces and or the RUC had been involved in the murder.

Ken Maginnis: No reason to assume collusion

But calls for a judicial inquiry have been rejected by Ulster Unionist Security Spokesman Ken Maginnis.

Speaking to the BBC he said: "I totally repudiate those who killed Pat Finucane."

Ken Maginnis: Collusion was unnecessary

But he added: "If Pat Finucane, as a member of a well known republican family, inextricably linked as he was with the IRA, was killed by loyalists it is not any reason to assume collusion unless like Mr Cumaraswamy you want to become a conduit for IRA propaganda."

The latest claims by Dublin by strengthen calls for a full an independent inquiry into the death of the civil rights lawyer Rosemary Nelson killed by loyalists in March this year.

Last month, Irish Prime Minister Bertie Ahern told the Irish parliament that allegations of police threats made against Ms Nelson "stood up".

He also highlighted continuing concern in Dublin about the status of the current police inquiry into the death of Ms Nelson, who was killed when a bomb exploded under her car as she drove away from her home in Lurgan, Co Armagh.