Nearly 20 people attended the flag-raising ceremony at Warrnambool's Civic Green on Sunday - the biggest turn out in about five years.

Australian West Papua Association south-western Victoria spokesman John Gratton Wilson said the event was an act of both support and defiance, as flying the flag was outlawed by the occupying Indonesian government.

He said some people in West Papua had been jailed for raising the flag that had been approved by the Dutch government in 1961 before Indonesia took control of the country soon after.

After more than a decade of campaigning, Mr Wilson said the way his West Papuan neighbours and friends were treated by the Indonesian government still made his skin crawl.

"I've witnessed personally the way the Indonesians treat the local people and in the last 12 months, the racial and religious tensions have arisen," he said.

"There are stories that you wouldn't want to repeat.

"They regard them as basically sub-human, but really we know who are the sub-humans in the way they treat other human beings."

Mr Wilson called on Australia's politicians and the United Nations to act, stating about 500,000 people had died in 50 years - an average of 200 people per week.

"It is wrong that we ignore these gross human right abusers on our doorstop," he said.

"The UN needs to acknowledge their mistakes from the 1960s and give indigenous West Pupuans a vote for self determination from a brutal oppressor."

Mr Wilson said a 2017 petition collected 1.8 million signatures in West Papua.

"I've seen a copy of the petition only two months ago. It weighs 40 kilograms, it's the biggest book in the world.

"Those 1.8 signatures is 70 per cent of the Melanesian population in West Papua and that has been handed onto the UN human rights commissioner Michelle Bachelet Jeria, and if that's doesn't indicate to the world that these people want freedom, then what does?

"West Papua will get freedom it's just a case of when."

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