A 43-year-old Bentleigh man being sought after a stabbing attack on two strangers and a suspicious fire that burnt down his mother's house could be armed and may strike again, police fear.

Senior Sergeant Eric Strik said police were asking for help to find Damen Stephens, but warned the public to stay away from him.

Police want to speak to Damen Stephens after two random stabbings in St Kilda and a suspicious fire at a Bentleigh house. Credit:Facebook

"There is certainly concern and risk that [he could strike again]," Senior Sergeant Strik said.

"We are not sure of his current state of wellbeing. We are warning people to be wary, stay away, and if they do sight him to call triple zero or call the police. Don't try to tackle him."