Sergeant Peter Radford of Williamstown police said the two policewomen, aged 35 and 37, were allegedly assaulted on The Esplanade shortly after 5.30pm.

"Two female members were patrolling that area on foot and they approached a couple of males who were verbally abusing people and taking photos of people at the beach," he said.

"They were extremely intoxicated."

Sergeant Radford said one of the men tried to evade police by riding away.

He tried to flee on his bike but was too drunk and fell off.

"The [police] members went to his aid and his brother confronted the members," Sergeant Radford said. "The bloke took a couple of swings at them, a couple of haymakers.

"Due to his aggressiveness and attempt to entice the members into fighting with him, he was subdued with capsicum spray."

Back-up units from Altona, Footscray and Laverton stations attended.

Sergeant Radford condemned the men's behaviour.

"We're just fortunate there were no injuries to the members and also to other members of the public.

"You've got two idiots down there disturbing everyone in the local area."

The brothers, aged 18 and 22, have been charged with assaulting police and resisting arrest.

Police are seeking witnesses to the incident.

Information: Williamstown police, 93939555.