Mr McAreavey has travelled to Mauritius to make a public appeal today for any fresh information which might convict the killers of Michaela, who was found strangled in the bath of the Legends hotel room where the couple were staying on their honeymoon in January 2011.
Michaela, daughter of Tyrone football manager Mickey Harte, was just 27.
Two former hotel workers were acquitted of her killing after a trial in summer 2012.
Since then there appears to have been little movement in the case, prompting Mr McAreavey to travel again to Mauritius to make a public appeal.
Accompanied by his sister Claire and brother-in-law Mark Harte, Mr McAreavey met Mauritian prime minister Pravind Jugnauth yesterday, in talks described by a spokesman for Mr McAreavey as positive.
Mr McAreavey also met with senior police personnel and later said: “We have had a short but positive meeting here today with the police. We have been updated on developments and how progress has been made. We are enthused by what we hear.
“We have communicated that we are very much involved in this process now. We are doing all we can to assist the Mauritian authorities in delivering justice for Michaela and the police now are very aware of what we are here to achieve.
"We are hoping and praying that in the next coming weeks and months we will be doing everything we can together to ensure justice is served.”
He said he had been assured the local police had detailed its elite task force to work on the investigation and added: “We hope that is the case and we hope they can do whatever they need to uncover fresh and compelling new evidence to get what we ultimately want, which is a retrial.”
Mr McAreavey also met Mauritian DPP Satyajit Boolell who he said was “fully behind what we are doing” .
Mr Boolell described it as “a very meaningful meeting” and said laws had been changed since the first trial and now offer “an important avenue for the police” in the situation where new evidence may emerge.
He said he hoped that “the very heinous crime” would not go unpunished.
Lawyer for Mr McAreavey, Dick Ng Sui Wa told local media the police had said they will do everything possible to find the culprits and that “an investigation is never concluded in the case of a murder case”.
Mr McAreavey will hold the press conference at the Labourdonnais Hotel at 9am Irish time today.