Mounted police have been forced to form a barrier between Reclaim Australia and Socialist Alliance protesters at opposing rallies in Melbourne.

Tensions among crowds have already led to scuffles and paramedics are treating several injured people.

Both sides are increasing in numbers, forcing police to stand in stand several rows deep in order to prevent further violence between the angry crowds.

Reclaim Australia are a group pushing nationwide rallies against "sharia law, halal tax and Islamisation".

Anti-racist protesters and other groups oppose their viewpoints.