Poor health has forced Northern Iron chairman David Griffiths to vacate his seat on the company's board.
Mr Griffiths had been a director of the Norwegian iron ore miner since 2007, and chairman since 2010.
It is understood his resignation was made to reduce his travel commitments.
A spokesperson for Automotive Holdings Group said the decision will not affect Mr Griffith's role as chairman of the car dealer network.
He is also deputy chairman of ThinkSmart and a board member of the Perth International Arts Festival.