A Man has holed himself up in a Clayton South house after reports of gunshots in the area, with police trying to talk him out.
Officers have closed Westall Rd northbound, near Heatherton Rd, after reports of shots being fired about 3.30pm.
A tradesman has told 7 News the gunman fired a rifle twice after an argument on a building site, with one of the bullets narrowly missing his workmate.
It is believed the gunman is still inside the house armed with the rifle.
Police do not believe the man is holding anyone else in the house, understood to be his own.
The Critical Incident Response Team is at the scene.
Drivers have been advised to seek an alternative route.