Two men, believed to be armed with a gun, are on the run after flipping a stolen car and ramming a police car in Melbourne's south-east.

The men were driving separate stolen cars - a black ute and a black Toyota Aurion sedan - when the ute flipped, crashing into a light pole, on Monahans Road in Cranbourne about 9am on Friday.

The stolen black ute that flipped on Monahans Road in Cranbourne Credit:3AW

Local resident Alisha, who lives nearby, told radio station 3AW other witnesses saw the black ute speeding out of a BP service station still attached to the petrol bowser shortly before the crash.

"They've come down too fast through the roundabout on Monahans Road and they lost control and flipped the vehicle," she said.