The deputy First Minister made the announcement on Thursday, as he met with the Mauritian High Commissioner in London.

Mr McGuinness said he would be guided by the opinion of John Larkin, who is also expected to liaise with his Mauritian counterpart.

He said he was in London to find out what actions the Mauritian authorities are prepared to take to find Michaela's killer, adding that he had been told there is "every prospect" of a new trial.

Earlier this week, the Mauritian prime minister called for PSNI and Garda to travel to the island, but Mr McGuinness said this must only happen "in the context of their being a new trial".

"That's absolutely essential. We cannot have a situation when people are just going to come and examine papers and just walk away," he said.

There's a very strong view that the McAreavey and Harte families have been very badly treated by the Mauritan justice authorities.

Martin McGuinness

Mr McGuinness previously stated that he disagrees with the verdict of the jury, which found Avinash Treebhoowoon and Sandip Moneea not guilty of murdering Mrs McAreavey in the luxury Legends resort last year.

He said the McAreavey family feel that Michaela's husband John was "put on trial" when he returned to the island for the court case.

The family has also condemned the publication of photographs the crime scene - including graphic images showing Mrs McAreavey's injuries - as "reprehensible and repugnant", adding that it "marks another low" in the handling of the case.

On Thursday the editor of the Sunday Times, the paper that published the pictures, collapsed in court.

Imran Hosany, who spent the previous night in police custody, was appearing on charges connected to the publishing of the pictures and to the assault of a press photographer.

He denies the charges, and was taken to hospital after his collapse during court proceedings.

The distasteful behaviour of one of the Mauritian newspapers in taking receipt of and publishing the crime scene photographs was an outrage.

Peter Robinson

"The authorities in Mauritius recognise that they have not covered themselves with glory in terms of the way the investigation was handled," First Minister Peter Robinson said.

"The way the courtroom proceedings unfolded, with senior lawyers considering it a matter of comedy routine while we are dealing with the murder of a young woman on her honeymoon, seems utterly preposterous and something that would never happen here," he added.

"Many people here are left wondering what chance there ever is of there being justice in this case."

Mr McGuinness said that he had spoken to John McAreavey's father Brendan and shared his view that there had been "an absolutely appalling miscarriage of justice".

The Irish ambassador to Mauritius, Brendan McMahon, is also now due to meet officials on the island.

Michaela, the 27-year-old only daughter of Tyrone GAA boss Mickey Harte, was found dead in the bathtub of her hotel room by her new husband during their honeymoon in January 2011.