Wong says she believes activists who say they were sexually assaulted in Israeli custody

Foreign Minister Penny Wong has said she believes the allegations of some Australian activists that they were sexually assaulted while detained by Israeli forces.

Senator Wong was asked about the allegations during a tense Senate estimates hearing.

The Israel Defense Forces has previously rejected claims of mistreatment towards the activists, and Australia has sought an urgent, transparent investigation.

Foreign Minister Penny Wong has told a parliamentary hearing she believes the allegations of Australian activists, who say they were sexually assaulted while detained by Israeli forces.

Warning: This story contains content that may be distressing.

Eleven Australians were detained while trying to reach Gaza as part of a humanitarian flotilla in May.

The Global Sumud Flotilla has since lodged a submission with the International Criminal Court alleging war crimes, crimes against humanity, torture and other breaches of international law.

Senator Wong was asked if she believed allegations of sexual assault made by some of the Australian activists.

During a tense Senate estimates hearing, Greens senator Mehreen Faruqi described allegations made by three of the women.

"One of the flotilla participants, Juliet Lamont, has said she was sexually assaulted, cable-tied and had so much water thrown in her face … she thought she was going to drown," she said.

"She says 'they wrenched my trousers and underwear down and I was raped by one of the soldiers' … other people had guns inserted inside them."

Senator Faruqi said that activist Neve O'Connor claimed she was sexually humiliated, and another activist Violet Coco alleged she had been sexually assaulted.

Eleven Australians detained by Israeli forces while attempting to deliver aid to Gaza have submitted evidence to the International Criminal Court alleging abuse, torture and other violations during their detention.

"My principle position is to always believe women when allegations of sexual assault are made," Senator Wong said.

"Those allegations are terrible, they are horrific, the treatment is unacceptable.

"I express my empathy to those women to whom that was done."

The Israel Defense Forces (IDF) has previously rejected claims that flotilla participants were mistreated while in custody.

"IDF orders require respectful and appropriate treatment of flotilla participants on the intercepted vessels, and there are clear and established procedures in this regard," it said in an earlier statement.

"No specific incidents of deviation from these binding procedures are known within the IDF. Any concrete co