On Friday, the Greater London Authority (GLA) said in a statement that it has asked the Independent Office for Police Conduct to assess whether it is necessary to investigate Johnson for the criminal offense of misconduct in public office.
"Allegations have been brought to the attention of the Monitoring Officer that Boris Johnson maintained a friendship with Jennifer Arcuri and as a result of that friendship allowed Ms Arcuri to participate in trade missions and receive sponsorship monies in circumstances when she and her companies could not have expected otherwise to receive those benefits," the monitoring office of the GLA said in a statement.
Arcuri and her company have not responded to CNN's request for comment. She told the Sunday Times, "any grants received and any trade mission I joined were purely in respect of my role as a legitimate businesswoman."
Downing Street declined to comment to CNN on the allegations, but Johnson said in BBC interview that everything was done "entirely in the proper way."
The Independent Office for Police Conduct is involved because Johnson was in charge of the Metropolitan Police as part of his role as mayor, said the statement.
The GLA has released a letter it sent to the Prime Minister, informing him it has referred the issue to the police watchdog.
In the letter, the authority's monitoring officer details instances of Arcuri's businesses allegedly receiving public money. These include two sponsorships -- one of £10,000 in 2013 and one of £1,500 in 2014 -- from London & Partners, the mayor's promotional agency.
The letter also lists three international trade missions in which Arcuri allegedly took part. According to the letter, she was allowed to take part in two even though her companies did not qualify. She participated in the third one after re-applying following an initial rejection.
The Oversight Committee of the Greater London Authority has given Johnson 14 days to provide the details of the relationship.