Detectives investigating the murder had arrested Dassen Narayen on Tuesday.
His lawyer Vikash Teeluckdharry said Narayen was questioned about allegations of theft at the Legends Hotel around the time of the Co Tyrone teacher’s murder on the Indian Ocean island.
He said his client denied any wrongdoing.
Mauritius Police Force have since said Narayen was brought before a district magistrate on a count of conspiracy to commit larceny.
Following Mrs McAreavey’s killing in 2011, Narayen was initially charged with conspiracy to murder but that was later reduced to a larceny charge.
Mrs McAreavey, 27, was strangled in her room at the hotel on January 10 2011.
The teacher, who had got married 10 days earlier, was attacked as she returned to her room alone and disturbed a burglary.
No-one has been convicted of murdering the daughter of famous Gaelic football manager Mickey Harte.
Two former workers at the luxury resort – Sandip Moneea and Avinash Treebhoowoon – were acquitted of murder after a high-profile trial on the holiday island in summer 2012.
Mr Teeluckdharry said Narayen was questioned about the same 2011 larceny allegations on Tuesday.
“He was questioned under warning, he was detained, he was arrested,” he told PA.
Mr Teeluckdharry said Narayen was taken to hospital during his police detention and was being treated for longstanding health issues in a hospital in the capital Port Louis on Tuesday night.
Mr Teeluckdharry claimed that police in Mauritius were attempting to suggest there had been a major development in the murder case.
“This is all nonsense,” he said. “There is nothing new.”
“He’s denied this from day one and it’s the same situation today,” he said.
Narayanen (37) has since appeared before a court where he has been charged with conspiracy to commit larceny.
A document from the court at Riviere du Rempart shows the charge relates to conspiracy to steal from the room where Mrs McAreavey and husband John stayed at the Legends Hotel resort in 2011.
A spokesperson for the Mauritius Police Force said he was arrested on Tuesday following advice from the country’s director of public prosecutions. He was remanded in custody until April 6.