The Financial Times reported overnight that British telecommunications giant BT Group is set to announce du Plessis as its new chairman later today.

Citing an anonymous source, the report said du Plessis would announce plans to step down from the Rio board within a year.

A Rio spokesman did not respond when contacted by MNN.

South African-born, London-based Du Plessis was appointed as chairman of Rio in 2009 at a tumultuous time for the company, when its profits had been hit by the global financial crisis and it was considering a $US19.5 billion deal with Chinalco.

He joined the board in 2008 and got the chairman’s job almost accidently when Paul Skinner’s replacement Jim Leng resigned after only a few weeks in the top role at Rio.

Skinner stayed on an extra month and du Plessis’ appointment was announced in March 2009.

He’s presided over three CEOs during his eight-year reign, with Tom Albanese being sacked in 2011 and replaced with Sam Walsh.

Walsh was replaced by Jean-Sebastien Jacques in July.

The news comes days after Rio admitted the investigation into payments made to a consultant over the Simandou iron ore project in Guinea could take years.

Main rival BHP will also appoint a new chairman this year after Jac Nasser announced plans to step down.

And only last month, Anglo American chairman Sir John Parker announced he would also step down this year.

Rio shares fell by 2% this morning to $A60.12, a two-month low.