David Constable and Sam Laidlaw will join the board immediately, while Simon Henry will become a director on July 1.

Constable is a Canadian engineer and former CEO of Sasol. He is a current director of ABB and Anadarko Petroleum Corporation.

Energy executive Laidlaw was CEO of Centrica and currently chairs Neptune Oil & Gas, as well as sitting on the board of HSBC Holdings.

Henry will join the board once he leaves his current role as chief financial officer of Royal Dutch Shell at the end of June. 

In welcoming the new directors, Rio chairman Jan du Plessis said they broadened the experience of the board and the international perspective.

"Each of them has an outstanding pedigree, having operated in upstream, capital intensive and global industries," he said.

"With diverse expertise across successful international engineering, resources and financial businesses, I have no doubt that their insight and hands-on experience will strengthen the board."

Current non-executive directors Robert Brown and Anne Lauvergeon will step down at the annual general meeting in May.

"I would like to thank Bob and Anne for the considerable contribution they have both made to the board over the years and for their wise counsel," du Plessis said.

"In Bob's case, I also want to acknowledge the additional demands of travelling from Canada to either London or Australia regularly over the past seven years."

As of July, Rio will have 12 directors, only two of which are female.