Caroline Kennedy calls Robert F Kennedy Jr a 'predator' ahead of confirmation hearing

Caroline Kennedy, the former US ambassador to Australia, has called her cousin Robert F Kennedy Jr a "predator" ahead of his confirmation hearings, urging American senators to reject him as the nation's health secretary.

Her letter, first reported by The Washington Post and later relayed in a video message by her son Jack Schlossberg, said RFK Jr was addicted to "attention and power" and had given hypocritical advice by discouraging parents from vaccinating their children while vaccinating his own.

"I have known Bobby my whole life; we grew up together," the former ambassador said.

"It's no surprise that he keeps birds of prey as pets because he himself is a predator."

RFK Jr, the nephew of former president John F Kennedy, will face confirmation hearings on Wednesday and Thursday, local time, in a bid to become the secretary of the Department of Health and Human Services (DHHS).

He has promoted disproven claims, including that childhood vaccines cause autism.

He has also been accused of fuelling vaccine scepticism in Samoa ahead of a deadly measles outbreak that killed 83 people there in 2019.

Kennedy said his views were "dangerous enough" to disqualify him from the role but his personal qualities posed an "even greater concern".

She went on to claim "the strength of his personality" led other family members "down the path of drug addiction."

"His basement, his garage, his dorm room were the centre of the action where drugs were available, and he enjoyed showing off how he put baby chickens and mice in the blender to feed his hawks," she added.

"It was often a perverse scene of despair and violence."

RFK Jr has openly talked about his heroin use and he pleaded guilty for bringing the drug on an airplane in 1984.

He was given "many second chances by people who felt sorry for the boy who lost his father [assassinated attorney-general Robert F Kennedy]", while going on to "misrepresent, lie, and cheat his way though life", his cousin added.

Caroline Kennedy accuses RFK Jr of exploiting JFK's death

Kennedy also condemned RFK Jr for using her father's assassination and that of his own father's to "grandstand" during his presidential bid.

She said she did not comment at the time due to her capacity as ambassador.

"It's incomprehensible to me that someone who is willing to exploit their own painful family tragedies for publicity would be put in charge of America's life and death situations," she said.

RFK Jr has applauded US President Donald Trump's move to declassify information on the killings of Robert F Kennedy and John F Kennedy, saying "a government that withholds information is inherently fearful of its citizens' ability to make informed decisions and participate actively in democracy".

His support was slammed by Kennedy's son, Schlossberg, who said the former president was being turned into "a political prop, when he's not here to punch back".

Responding to his mother's letter to senators, Schlossberg said he was proud of his mother "who's lived a life of dignity, integrity and service".

Kennedy gave a farewell address to Australia in November, using a National Press Club speech to call RFK Jr's views on vaccines "dangerous".

"I don't think most Americans share them," she added at the time.

Trump is yet to announce his replacement for the Australian role.

-ABC

*This story was first published by theABC.