The March in March demonstration was designed to voice a lack of confidence in the federal government's policies and decisions.

Marchers heard from a handful of speakers on a range of progressive political topics including the treatment of asylum seekers and climate change.

Greens leader Nick McKim and Denison MHA Cassy O'Connor were among those taking part in the peaceful protest.

The Hobart march coincided with tens of thousands of protesters marching through city streets right across Australia, waving placards vilifying Prime Minister Tony Abbott and venting their anger at conservative policies.

The March in March event attracted the largest crowd in Melbourne, where more than 10,000 people - among them parents, students, environmentalists, refugee supporters, cab drivers, teachers and children - gathered in the city centre.

About 2000 swarmed on central Brisbane to show their disdain for the direction taken by Liberal governments and just under 10,000 protested in Sydney.

Many of the headline- grabbing polices of the Commonwealth, New South Wales, West Australian and Queensland governments were attacked during an event organisers say is a grassroots, non-partisan peaceful protest spawned from conversations on social media.

The organisers claim March in March has 45,000 Facebook supporters, amassed since the conversation began in January.

Speeches on indigenous rights, asylum seekers, education funding and university cuts featured in the Melbourne march, which 17,000 people said on Facebook they would attend.

"Transit not tolls" and "Turn back the AbBoat" signs were brandished by members of the eclectic crowd.

In Sydney, placards suggesting Mr Abbott has Satan on speed-dial and others denouncing the illuminati and global weather conspiracies were waved as rain fell on the park hosting the event.