A pregnant woman was among dozens of people punched, kicked and abused during a brawl that erupted during a football game in Melbourne's outer-west, according to a witness.

The ugly fracas took place during a division 3 Western Region Football League game in Tarneit on Saturday, the Herald Sun reports .

It is understood up to 150 fans will now be investigated as a result of the fight, which was filmed by onlookers.

Footage shows a group throwing punches and kicking rival fans just metres from the game, which was being played between Newport Power and Parkside.

An unnamed witness said he took two children to safety to escape the violence.

"It was like the Cronulla riots – that is what it felt like," the witness told the Herald Sun.

"It was massive. It was a free-for-all.

Up to 150 supporters are now reportedly being investigated. (Herald Sun)

"There was a bloke with sticks belting everyone from behind in the head."

The witness said the pregnant woman was kicked by up to 20 people.

"It was crazy, this lady was about eight months pregnant," he said.

"If she miscarries these guys go back to wherever they live and they get away with it."

Both teams have said they do not know what started the fight.