Millionaire businessman Ken Ong will run for lord mayor of Melbourne, saying the city council needed "stability" in the wake of the departure of Robert Doyle.

Mr Ong, the former chair of planning at Melbourne City Council and a councillor for eight years, on Thursday said he would stand in May's lord mayoral by-election.

Ken Ong was a Melbourne councillor for eight years.

The byelection is being held after Mr Doyle quit following an investigation into sexual harassment allegations against him. Mr Doyle, mayor for nine years, denies the allegations.

"After all the turmoil, I will be able to bring the stability that the city needs," said Mr Ong, who has made millions of dollars from his businesses, which include childcare, regional property and brewing.