The grass roots events labelled March In March gained momentum on social media after online groups were created in January.
In Sydney, the Facebook event attracted more than 12,000 responses and the hashtag #MarchInMarch trended across Titter on Sunday.
Musician Billy Bragg was among the social media users promoting the event online before addressing the crowd in Belmore Park.
“I'll send this song out to Gina Rinehart and those people who somehow think that people on welfare are cheating them,” he said.
“They're not. Those people on welfare are just like us. That safety net is there for all of is. We support it, we lose it at our own personal peril."
The three-day event continued in Canberra on Monday, when a statement of no confidence in the Abbott government was due to be delivered to Parliament House.
The event in the national capital attracted an estimated crowd of hundreds, including voters who had travelled from regional and rural Australia.
Issues such as the environment, same sex marriage and Indigenous policy were among those on the agenda.
Free Iran Project advocate Kavuh Akvari addressed attendees in Sydney on the country’s attitude to immigration.
“We have moral responsibilities,” he said.
“I think both our media and our politicians are on a position where they can create this culture of acceptance… I think there is a better approach we can take.”
The events were also widely criticised across social media, where users pinpointed abusive signs gesturing to violence against politicians and Tony Abbott.
Head of the Prime Minister’s Indigenous Council Warren Mundine weighed in on the debate online, describing the event as a “total time waste” on twitter and its attendees as “w—kers”.
Canberra organiser Loz Lawrey says the idea started as a conversation between a handful of people on Facebook in January.
"They said to each other, we can't just keep complaining to each other about this government, we have to do something about it," Mr Lawrey told AAP.
"As that conversation became more public, people started saying: We'd like to be involved."
He says the movement has 45,000 supporters.
Federal Opposition Leader Bill Shorten distanced himself from the rally, telling reporters the Labor Party was not formally involved.
"But I do get people want to express their views. It's a free country," Mr Shorten said.
Prime Minister Tony Abbott told reporters he thought the only large rally being held in Sydney was to do with St Patrick's Day.
The events coincided with the election of a Liberal Government in Tasmania, leaving the ACT as the only Labor led state government in the country.
Negotiations with Independents continue in South Australia following the weekend election.
