Caroline Kennedy, the daughter of the late US President John F. Kennedy, has called for US senators to reject the nomination of her cousin, Robert F. Kennedy Jr., to lead the Department of Health and Human Services. She says he is unqualified for the job.

US media reported that she sent a letter to senators on Tuesday, urging them to turn down the nomination of President Donald Trump's pick of Robert F. Kennedy Jr. for health secretary. Media also carried a video of her reading out the letter she had written.

Caroline Kennedy has served as a former US Ambassador to Japan. In the letter, she wrote that overseeing the official agencies that are charged with protecting the most vulnerable among us "is an enormous responsibility and one that Bobby is unqualified to fill."

She also pointed out that he lacks relevant government management or medical experiences and said, "his views on vaccines are dangerous and willfully misinformed."

Robert F. Kennedy Jr. has worked for environmental protection as a lawyer. He is also known for his anti-vaccine views. He has questioned the safety of vaccines, based on information that allegedly lacked scientific grounds. He insists that some vaccines can cause autism.

Trump's nominee for the health secretary is soon to appear before Senate confirmation hearings.