The billionaire sultan of Johor state has been sworn in as Malaysia's new king under the nation's unique rotating monarchy system, Report informs, citing Sky News.

Sultan Ibrahim Iskandar, 65, took his oath of office at the palace and signed the instrument of the proclamation of office in a ceremony witnessed by other royal families, Prime Minister Anwar Ibrahim, and cabinet members.

A coronation ceremony was held then.

Under the unique system, the heads of Malaysia's nine royal families take turns to be the King, known as the "Yang di-Pertuan Agong" every five years.

Nine ethnic Malay state rulers have taken turns as King for five-year terms under the world's only such system since Malaysia gained independence from Britain in 1957.

Sultan Ibrahim's election to the national throne by his fellow rulers in October was widely expected based on an established rotation order.

Sultan Nazrin, the ruler of Perak state and next in line to the throne, was re-elected as deputy monarch.