Police have arrested a man after a five-hour siege in Ballarat, west of Melbourne, after the man barricaded himself inside a home.

The man is believed to have locked himself inside a unit on Napier Street in the suburb of Black Hill after a brawl with four others at 8:00am (AEDT) today.

The other four men left in a car before police arrived at the scene.

After police negotiations the man inside the unit was arrested shortly before 1:00pm.

Police say they have found two rifles and other weapons in the flat.

Senior Sergeant John Gibson says they are yet to find the other men.

"We'll see where the evidence leads us and to what involvement these four males had in the incident itself," he said.

The man has been taken to hospital with injuries sustained in this mornings fight.