Questions about who was the source of the plan to use private security for Victoria's hotel quarantine program remain after former Victorian police commissioner Graham Ashton strongly denied he pushed for the option.

Giving evidence to Victoria's hotel quarantine inquiry on Thursday, Mr Ashton, who recently retired, said he first became aware that private security would take the lead role after being told by Emergency Management Commissioner Andrew Crisp at a meeting at 2pm on March 27 at the state emergency centre.