Far-right nationalists with links to anti-immigration rallies have defaced a street art poster campaign in Brisbane designed to challenge ideas of Australia’s national identity.

It comes after one of the group claimed responsibility for a series of offensive posters plastered around Sydney and Melbourne earlier this year depicting Bondi shooter Naveed Akram.

Self-proclaimed Australian nationalist and content creator Andre Mamet, who goes by the handle “Ausmaxx”, and Melbourne stockbroker Mitch Hobbs, aka “Sir Doug”, filmed themselves vandalising the posters in locations including South Brisbane’s Fish Lane and Norman Park over the weekend.

Federal Labor MP Renee Coffey shared video of her using a “step ladder, squeegee on a pole and my tallest son” to remove the words “Indian”, “Chinese”, and “not” which had been plastered over the distinctive “Aussie” label at Norman Park station in her seat of Griffith.

“When my son asked me where we were going, I said: ‘to fight racists’,” Coffey said.

Adelaide-based artist Peter Drew launched the “Aussie” poster series in 2016 in response to what he saw as rising anti-immigration sentiment and xenophobia. It depicts Australians citizens who had been subject to the White Australia Policy.

He revived the series earlier this year to mark its 10th anniversary, and in response to the March for Australia anti-immigration rallies that began last August.

After visiting Sydney and Melbourne, Drew travelled to Brisbane at the end of July to erect 150 posters across inner-city suburbs and in Ipswich, where far-right politician Pauline Hanson ran a fish-and-chip shop before launching a political career.

He told this masthead he was not fazed by Mamet and Hobbs’ “latest brainwave”, adding that the point of the series was “to get under their skin”.

“What we’ve got is a very small cohort of lost boys who are testing their ideology against reality, and every time it gets knocked back,” Drew said.

“I like engaging with them and I don’t dislike them as people – it’s their ideas that I content with.

“When things like this happen … it keeps me going more than anything else.”

Coffey said she did not support illegal street art but was delighted when Drew’s work appeared in Brisbane.

“Peter Drew’s iconic artwork represents an inclusive, warm, welcoming Australia that I believe in, and challenges narrow, exclusionary definitions pushed by our political opponents,” she said.

“Racism has absolutely no place in our community, as evidence by the number of locals who shouted out ‘thank you’ and passers-by who stopped to help us [on Sunday].”

Mamet told this masthead: “Peter Drew’s art, despite being illegal graffiti, and as explained by him is used to deconstruct Australian identity, is celebrated and allowed.”

He did not elaborate further on the pair’s motivation to deface the works.

Hobbs was also contacted for comment.