Caroline Kennedy slams 'predator' cousin Robert F. Kennedy, Jr

Caroline Kennedy has slammed her cousin Robert F. Kennedy, Jr, describing him as a "predator".

The daughter of former President John F. Kennedy read out an open letter to the US Senate, urging its members not to appoint her cousin Robert F. Kennedy, Jr, to the role of Health and Human Services Secretary.

"He lacks any relevant government, financial, management or medical experience. His views on vaccines are dangerous and wilfully misinformed," Caroline, 67, said, reading aloud the letter aimed at members of America's Senate Health, Education, Labor and Pensions Committee.

"These facts alone should be disqualifying, but he has personal qualities related to this job, which for me pose even greater concern."

Robert, 71, has been outspoken against the use of vaccines to prevent disease and, if his nomination to the role is successful, is expected to overhaul the country's vaccination schedule.

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

"He's always been charismatic, able to attract others through the strength of his personality, his willingness to take risks and break the rules."

The former first daughter added she "never wanted to speak publicly about my family members and their challenges" but her fears left her feeling compelled to do so.

"They (the public) deserve better than Bobby Kennedy, and so do the rest of us. I urge the Senate to reject his nomination," she said.