Australian children from Muslim, Greek, Catholic, Jewish, Armenian, Anglican and Indigenous backgrounds are hanging out together to help stamp out racism.
The message for Friday's Harmony Day is that Australians must not become complacent about racial intolerance.
The day coincides with the UN's day to eliminate racial discrimination and celebrates Australia's cultural diversity, with more than seven million migrants arriving here since 1945.
Chairman of the Federation of Ethnic Communities Council of Australia, Joe Caputo, said most Australians do appreciate the benefits of a multicultural society but instances of racial discrimination and harassment occur daily.
"We must continue to advocate the need for strong action against destructive elements in our society that attempt to erode our country's rich cultural diversity," he said in a statement.
Around 45 per cent of Australians were born overseas or have a parent born overseas, according to census data.
NSW Senator Concetta Fierravanti-Wells says cultural diversity is worthy of a national day celebrated through sport, dance, art, film, music, storytelling, cooking and sharing cultural meals.
Around 6500 Harmony Day events are being held around the country on Friday.
Orange has been the official colour of support since the first the day was first held in 1999.
A "Respect, Understanding, Acceptance" program run by the NSW Jewish Board of Deputies will bring school children from many backgrounds together next week.
The aim is to stop bigoted messages coming from the homes of some children.
Attendees will be taught "if you're a bystander, you're part of the problem".
