US Secretary of State Marco Rubio has announced an envoy to promote the protection of Tibetans living under Chinese rule, in a rare return under the Trump administration to championing human rights.

Rubio announced that Riley Barnes, the assistant secretary of state for democracy, human rights, and labor, would serve as the US special coordinator for Tibetan issues.

"The United States remains committed to supporting the unalienable rights of Tibetans and their distinct linguistic, cultural and religious heritage," Rubio said in a message for Losar, the Tibetan new year.

A top priority for US policymakers in recent years has been to defend Tibetan religious rituals in selecting a reincarnation for the Dalai Lama, amid fears that China will seek to identify and groom a compliant successor to the 90-year-old spiritual leader.

The special coordinator position is required by an act of Congress passed in 2002.

Successive administrations have designated senior officials to serve concurrently in the role, although President Donald Trump in his first term waited months before making an appointment.

Trump has focused heavily on trade in his relationship with China, which he plans to visit in April.

Rubio, speaking Monday in Hungary, noted that China has the second largest economy and nuclear weapons and said it would be "insane for United States and China not to have relations and interact with one another."