Writer and social commentator Van Badham called to the thousands who once again assembled outside State Library to protest against the Coalition's budget cuts to education, health care, the ABC and its policies regarding refugees.

Although reaching the thousands, the crowd failed to top the 30,000 who rallied against the budget in March, with police estimating crowd numbers to be about 5000 at their peak on Sunday afternoon.

Emotions - and passions - ran high,  with many protesters waving banners saying, "Abbott, you're un-Australian", "$100,000 degrees? I won't vote for this" and "This is a bad joke - and I'm not laughing" as part of a series of national protests to "bust the budget".

The protest was one of 27 around the nation.

Protester Mary-Lou McPherson, who was holding the sign, "Shame, Abbott, Shame", said she and her friend Louise could no longer stay home and watch the government target vulnerable communities.

"I knew it would be tough, but it's just the lack of compassion and Abbott's lack of insight into the communities that need the most help that's terrible"  she said.

Louise Ivers, whose young daughter suffers from a mental illness, said she needed to find other avenues to help her since the cuts to health care were made.

"I've got a little girl who needs a bit of help, and because the funding's been cut, she won't havea counsellor until Christmas," she said.

In the meantime, a giant and grotesque-looking Tony Abbott puppet - complete with smoking pants - parted the startled crowd, eliciting cries of "Liar, liar, pants on fire".

Outside Parliament House, where the march ended, speakers such as human rights and refugee lawyer Julian Burnside, Jennie Hall from Destroy the Joint, and Greenpeace chief executive David Retter took to the stage to rally against the government.

But it was 18-year-old high school student Marlee Gorman who caused the crowd to roar with indignation as he talked about the debt facing his generation.

"I couldn't vote in the last election, but I am going to suffer," he yelled.

Victoria Police Inspector Steven Cooper told media that the protesters had behaved exactly as they should.

"They stuck to their plans, it was peaceful from our end, and it went exactly as it should have," he said.

He estimated that numbers dropped off during the speeches, with about 3000 people remaining just after 3pm when the protest concluded.