The artist behind a controversial portrait of mining magnate Gina Rinehart has weighed into the row, saying “people don’t have to like my paintings”.

It came as more details emerged about how the National Gallery of Australia found itself at the centre of a high-powered campaign against the “offensive” work by award-winning artist Vincent Namatjira.

An Olympic champion and a state swimming organisation have been revealed as the main drivers of demands to remove the portrait of Australia’s richest woman.

The work is one of 21 portraits in an installation titled Australia in Colour. Acquired by the gallery as part of its 40th anniversary celebrations in 2022, it is on show as part of Namatjira’s first major survey exhibition, which opened in Canberra in March.

“I paint the world as I see it,” Namatjira said in a statement on Thursday.

“People don’t have to like my paintings, but I hope they take the time to look and think, ‘why has this Aboriginal bloke painted these powerful people? What is he trying to say?’.

“I paint people who are wealthy, powerful, or significant – people who have had an influence on this country, and on me personally, whether directly or indirectly, whether for good or for bad.

“Some people might not like it, other people might find it funny, but I hope people look beneath the surface and see the serious side too.”

The portrait of Rinehart sits alongside images of Queen Elizabeth II and football player Adam Goodes. It will be on display until July 21.

It was previously on public display at the Art Gallery of South Australia for the exhibition’s initial run. The SA gallery received no requests to remove the painting.

Rinehart, who is listed as a friend of the National Gallery for making donations of $5000-$10,000, is yet to make any public comments about the issue.

But it has emerged that Swimming Queensland chief Kevin Hasemann wrote to NGA director Nick Mitzevich in April – at the instigation of Rio Olympic gold medallist Kyle Chalmers.

“[Chalmers] asked could Swimming Queensland assist the swimmers there to approach the gallery and to make the gallery aware of the way that they were perceiving it, which is what we did,” Hasemann told ABC Radio Brisbane on Friday.

“We confirmed that a significant number of swimmers felt that way.

“Having seen the portrait myself, it made sense that we would respectfully – and I emphasise respectfully – contact the gallery, make them aware of the way that we were perceiving it and hope that they might consider taking it down.”

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Hasemann said the letter had “blown into something that I never could have imagined”.

“I don’t know why we have to defend ourselves,” he said.

“We simply, privately did what the gallery actually encourages. It says it likes debate. It actually encourages that.

“This is Australia. It’s a democracy. You’re allowed to disagree. You’re allowed to express your opinion, and that’s what we did.

“What we said was that we thought that it was unflattering and offensive and would they mind taking it down. That’s all we said.”

Chalmers has told the Nine papers there was plenty of support in swimming for Rinehart – “our patron that makes everything possible for us”.

“I think she just deserves to be praised and looked upon definitely a lot better than what the portraits have made her out to be. Without her sponsorship, we would actually have nothing,” he said.

Rinehart has poured more than $40 million into sponsorship through Swimming Queensland and her company’s Hancock Prospecting Swimmer Support Scheme.

In 2023, she withdrew a $15 million sponsorship of Netball Australia after Indigenous netballer Donnell Wallam asked for her uniform not to carry Hancock Prospecting’s logo.

Rinehart later set up a $3 million fund to reward athletes who won gold medals or set world records in swimming, artistic swimming, rowing and volleyball.

The gallery maintains it will not remove the work, while the art world has defended it. Critic John McDonald said there was little anyone who objected to a portrait of themselves could do.

“Fundamentally it’s a work of satire and it’s impervious to these complaints,” he told the ABC’s The World Today.

“If we start complaining about satire, politicians would be always complaining about every cartoon. If you put yourself up there, a public figure – because she’s always had something to say, she likes to exert influence – you’ve got to learn to take it.”

-with AAP