Tim Soutphommasane says Australia needs to acknowledge forms of racism that appear “with the face of respectability” and not dismiss racist acts done with good intentions if it is to have a racially equitable society.

Speaking at a Deakin University conference on institutional racism in Melbourne on Wednesday, the race discrimination commissioner said that many Australians took the suggestion that racism exists in Australian society as “a grave insult” and said that reaction prevented a proper national conversation around race and equality.

“The bar is set very high within public discourse on what constitutes racism,” Soutphommasane said. “In the minds of many people ... something is only really racist if it involves an expression or outburst of some kind.

“Nasty abuse, violent vilification, physical assault, the Klu Klux Klan ... anything short of that severity of racial superiority or doctrine is not truly or really racism.”

Soutphommasane said that if you define racism as only existing in those extreme terms, people believe that only “bad people” are racists and, conversely, “good people” cannot be racist.

“Too often people can excuse or justify an act or a state of affairs by explaining away that there was no malice involved,” he said. “People forget that racism is as much about impact as it is about intention. Just because someone doesn’t have evil in their heart doesn’t mean that a person wasn’t harmed by a racist act.”

He also spoke about the need to achieve racial equity, not just racial equality, as a necessary step to ensuring equal rights and representation.

His comments come a week after the Turnbull government announced it would not support a proposal to enshrine a representative Aboriginal and Torres Strait Islander body in the constitution to advise the government on Indigenous affairs because, among other objections, it was “inconsistent with the fundamental principle” that all Australian citizens should have equal civic rights.

Soutphommsane said that while Australia had eradicated most of its explicitly racist laws and policies, it retained “a more banal form of racism, one that can appear with the face of respectability”.

“It doesn’t need to involve physical violence or threatening abuse; it can be perpetrated perfectly well with a pleasant smile and good manners,” he said. “Structural racism needn’t involve people signing up to racist beliefs or attitudes. Prejudice, ignorance, thoughtlessness, indifference; these all add up to what we would understand as racism.”

Soutphommasane was appointed the race discrimination commissioner in 2013 and has held the position throughout the national debate to repeal section 18C of the Racial Discrimination Act 1975, which Liberal MPs have described as an “ideological goal” for conservative members of the Coalition.

Those who lobbied for the repeal argued that it was about representing the views of “mainstream Australia” who felt dictated to by minority concerns.

The repeal was blocked by the Senate in March.

Soutphommasane said the 18C debate “revealed an ongoing contest about who constitutes mainstream Australia”, particularly because a Fairfax Ipsos poll found that 78% of voters supported the existing 18C provisions, which make it unlawful to offend, insult or humiliate someone on the basis of their race or ethnicity.

“If there’s one telling lesson from the debate we have had on the Racial Discrimination Act, it’s that mainstream Australia may no longer be the group some people have in mind,” he said.

He said that Australia had embraced multiculturalism and diversity but was still not very good at talking about race, racial difference and racial equity, and that framing those conversations around events such as “harmony day” frustrated a serious debate.

“It’s one thing for us to talk about differences if it means talking about different foods of cuisines. How telling it is that we resort, when we talk about multiculturalism, to culinary diversity,” he said. “If only things were as easy as embracing culinary diversity. We would have eradicated racism by now and set a template for the world.”

He said that without strong commitments from political leaders on addressing racial inequality, achieving change would be “nigh on impossible”.

He also argued that white Australians should not be left out of meaningful conversations about race because they still made up the majority of people in Australian society.