Unite Against Racism: Migrants and Refugees Are Welcome events will be held on Sunday in Sydney, Melbourne, Canberra, Brisbane, Perth and Adelaide.
Organisers say the March for Australia rallies, which are also being held in most capital cities about the same time, are racist, with Nazis involved in some events.
"The far right is organised, violent and on the march," Greens senator Mehreen Faruqi said.
"Yet political leaders refuse to grapple with the reality of white supremacy and racism that is threatening and harming First Nations people and people of colour every day."
A collection of unions and community groups has organised the counter-protest.
"The danger posed by the far-right is imminent and rising," Labor for Civil Liberties convenor Shannen Potter said.
"Labor needs to wake up to the threat posed by fascism, and join with the community in showing Nazis and the far-right that they aren't welcome here.Â
"Our democracy won't defend itself."
The counter-demonstration organisers allege the March for Australia social movement wants to introduce Trump-style deportation laws that allow the government to send non-citizens to Nauru.
They said it was shameful that politicians such as Pauline Hanson and Bob Katter spoke at March for Australia rallies in August and alleged former opposition home affairs spokesman Andrew Hastie was fuelling racism with false claims about the housing crisis being caused by migrants.
The rallies come after ABC News published a video appearing to show a key March for Australia organiser co-ordinating with a Neo-Nazi at the movement's first rally in Sydney in August.
About 50,000 people reportedly gathered at March for Australia events across the nation in August, gaining significant media attention.
Parallel counter-demonstrations were also held on the same day.
16°C