An Italian prosecutor's claims that Maltese authorities had failed to cooperate with an oil smuggling investigation in Italy were "completely unreasonable, untrue and unjust," the Justice Ministry said this afternoon.

Carmelo Zuccaro, a chief prosecutor in Sicily leading a fuel-smuggling inquiry, was quoted in the Guardian today as saying an international request for cooperation to Maltese investigators had gone unanswered for 18 months.

Malta was “becoming a sort of crime haven for all kinds of mobsters,” he said.

Mr Zuccaro suggested there could be links between the fuel smuggling racket under investigation and the murder of journalist Daphne Caruana Galizia, saying that Ms Caruana Galizia had written about some of the people involved in his inquiry.

Malta's Justice Ministry has, however, rebutted Mr Zuccaro's claims that his request for cooperation was ignored, saying thast the matter was currently before the courts.

Italian authorities had sought cooperation in October 2016, the ministry said, through EU judicial cooperation agency Eurojust.

The Office of the Attorney General started procedures in local courts to collect the evidence request "in less than three months", the ministry said.

"Magistrate Claire Stafrace Zammit subsequently held two sittings for the collection of the evidence requested by the Italian authorities, and a third sitting has already been scheduled in the coming days," the ministry added as it rejected claims that it had an interest in not cooperating with other jurisdictions on the case.