Unions are expecting more than 150,000 protesters to shut down the CBD on Tuesday morning as a part of a nationwide series of rallies organised by the ACTU.

The ACTU's Change the Rules campaign is ramping up ahead of the state and federal elections.

A similar rally brought Melbourne to a standstill in May. Credit:Justin McManus

A similar rally in May caused large disruptions across Melbourne.

Roads were closed and trams delayed when more than 100,000 workers took to the streets.