Police are investigating why Iosif Galea was not arrested in Malta and was allowed to leave the country multiple times despite being subject to a European arrest warrant, Home Affairs Minister Byron Camilleri has told parliament.

Camilleri said he had spoken to the police commissioner, who informed him there is an internal investigation into the case.

"If any wrongdoing results from the investigation, all the necessary steps will be taken," he said while replying to a parliamentary question by PN MP Beppe Fenech Adami.

"Whenever an allegation of wrongdoing comes to my attention, I make sure it is investigated," said Camilleri.

"But it has to be related to the administration. I will not go into the criminal investigations, because that is not my place. That is the court's competence."

Fenech Adami asked Camilleri to outline what he knows about the case and whether there are criminal proceedings against Galea.

Home affairs minister Byron Camilleri says he will take 'all necessary steps' if any police failures are found.

Galea, a gaming consultant, had been wanted by German authorities since last year but was only arrested in mid-May while on holiday in Italy with a group that included former prime minister Joseph Muscat.

Contacted for comment, Muscat said he was not aware of the arrest warrant and he has never had any personal or professional relationship with Galea. They were only in the same group together because Galea was the boyfriend of a long-time friend.

Galea is expected to face charges in Germany related to financial crime, including tax evasion, but he is also wanted over a separate money laundering and tax evasion case in Malta.

Galea had been subject to a European Arrest Warrant since early last year, but police sources told Times of Malta he travelled out of Malta at least two other times before he was finally arrested in Italy earlier this month.

The story raised questions about how he was not arrested before and why he was allowed to travel multiple times out of the country.

In parliament on Monday, Fenech Adami and two other PN MPs, Mark Anthony Sammut and Karol Aquilina, followed up with a number of other questions but the minister remained reluctant to give further details.

They asked who was carrying out the investigation and why the police did not visit Galea's home, despite the fact he lives near a police station. 

Times of Malta asked the Maltese police about how Galea was allowed to repeatedly travel out of Malta despite being the subject of a German arrest warrant. 

They said that in view of Maltese legislation, they are "not in a position to confirm or otherwise such information".