Lawyers for Britain's Prince Andrew on Monday hit back at claims the royal was not cooperating with US prosecutors investigating the late financier Jeffrey Epstein, suggesting they were seeking publicity rather than his help.

“The Duke of York has on at least three occasions this year offered his assistance as a witness to the DOJ (Department of Justice),” Andrew's lawyers said in a statement.

“Unfortunately, the DOJ has reacted to the first two offers by breaching their own confidentiality rules and claiming that the Duke has offered zero cooperation. In doing so, they are perhaps seeking publicity rather than accepting the assistance proffered,” the statement said.

US authorities seek to question Prince Andrew

US investigators want to interview Andrew, Queen Elizabeth's second son, about his friendship with Epstein, who was found dead in prison last year while awaiting charges of trafficking minors, a US law enforcement official, who has direct knowledge of the investigation, said on the condition of anonymity.

Britain's Sun newspaper reported earlier on Monday that the DOJ had sent British authorities a mutual legal assistance treaty (MLAT) request, used in criminal investigations to gather material from other states which cannot readily be obtained on a police cooperation basis.

A spokeswoman for the Justice Department declined to comment. Buckingham Palace declined to comment. Britain’s Home Office said it did not comment on the existence of any MLAT requests.

Andrew, 60, who has not been accused of any wrongdoing, said in a public statement in November that he was stepping down from public duties because of the furor over his links to Epstein and would be willing to help “any appropriate law enforcement agency with their investigations, if required”.

In March, Manhattan-based US Attorney Geoffrey Berman said that despite the British royal publicly stating he would cooperate with the inquiry, the prince had “shut the door on voluntary cooperation and our office is considering its options”.

“Legal discussions with the DOJ are subject to strict confidentiality rules, as set out in their own guidelines,” a source close to the prince's legal team said in response to the Sun report.

“We have chosen to abide by both the letter and the spirit of these rules, which is why we have made no comment about anything related to the DOJ during the course of this year. We believe in playing straight bat.”

If the MLAT request was granted, US prosecutors could ask for Andrew to voluntarily attend an interview to give a statement or potentially force him to attend a court to provide evidence under oath.

A US Federal Bureau of Investigation probe is focusing on British socialite Ghislaine Maxwell, a longtime associate of Epstein's, and others who facilitated the wealthy financier's alleged trafficking of underage girls, law enforcement sources told Reuters in December.

Ghislaine, whose whereabouts are currently unknown, has denied the allegations against her.