Twenty years ago, a racially offensive comment by Collingwood ruckman Damian Monkhorst to Essendon's Michael Long brought the matter of racial abuse in the game to a dramatic climax.

On Wednesday, at a media conference to publicise this year's Long Walk before the Dreamtime at the 'G game on May 30, Monkhorst appeared in a Long Walk T-shirt and said: "I'm here to support Longie."

Long, for his part, thanked Monkhorst "for his leadership and goodness", and said he had "enormous respect" for him.

It was as a result of the fallout from the altercation between Long and Monkhorst that the AFL was hurried into formulating a policy on racial and religious abuse.

At the same time, the culture of the game flipped 180 degrees. Whereas a few months before, the prevailing attitude had been that "what happened on the field stayed on the field", the AFL found itself catapulted into being a national leader in the area of race relations.

Speaking on a panel that included former AFL CEO Ross Oakley and former Essendon and Greater Western Sydney coach Kevin Sheedy, Monkhorst said he had made a "terrible mistake" in racially abusing Long.

"I was young, I didn't really understand. But I'm really proud of Longie and the way he stood up for the cause."

Monkhorst, now an assistant coach for Hawthorn, said the most important thing for him now "is for people to understand what making these comments means".

He said he was "pleased for the Aboriginal boys today, because they can enjoy the game".

Monkhorst said it was after he retired that he began to think more seriously about the incident. "I had to explain it to my sons. As a parent, you hope they will learn from your mistakes."

The big man spoke with sincerity and conviction, and at one point was applauded by Aboriginal people in the audience.

Both Long and Monkhorst said they had received death threats during the drama of 20 years ago.

"But I had a lot of support too," said Long. "It wasn't always easy, but I could see what the game could do to promote change. Deep down we knew we were going to make a change."