Angered at a land rights announcement by then-prime minister William McMahon, the Indigenous men - Michael Anderson, Billy Craigie, Bertie Williams and Tony Coorey - set up their protest on January 26, 1972, outside what was then Parliament House, hoisting an 'Aboriginal embassy' placard supported by the umbrella.

The embassy was set up to pay homage to the Indigenous people never having ceded sovereignty or engaging in any formal treaty process.

Activist Gary Foley surmised decades later that, "the government had declared us aliens in our own land, so like other aliens, we needed an embassy".

Ngambri-Ngunnawal elder Matilda House Williams told AAP the struggle was ongoing.

"Just because 50 years have gone by, the struggle of maintaining rights, for land rights and all those other inequalities is still there," said Ms House Williams, who has supported the tent embassy since its inception.

"(The government) say all these wonderful things but we still have the struggle of carrying on, of still not having the things other people have in this country have."

Indigenous Australians have a shorter life expectancy than non-Indigenous people and are over-represented in prison, government data shows.

Ms House Williams said the voices of Indigenous people were often ignored in government consultations, compounded by the fact there is still no official treaty.

She said the protest needed to continue beyond the 50-year anniversary on Wednesday.

"The fight still carries on."

The Aboriginal Tent Embassy was removed and revived on several occasions in its early days, after attracting immediate attention from the then federal government and police force. It has occupied several other sites around Canberra before returning to its original location in 1992 on the 20th anniversary of the protest.

The Aboriginal flag was recognised as an official flag of Australia in 1995, and the embassy was listed by the Australian Heritage Commission as a place of special significance that same year.

Indigenous senator Malarndirri McCarthy said five decades on, the embassy is still a sign of things left undone.

"The tent embassy is a symbol of unfinished business in Australia on issues such as racism, inequality, and the need for healing as a nation," Senator McCarthy told AAP.

"They still need economic equality to be able to flourish on homelands, communities and cities. First Nations youth are incarcerated at such high rates, and deaths in custody reflect the continued failure of Australian governments."

Indigenous Affairs Minister Ken Wyatt said the tent embassy remained a focal point for many of the adversities faced by Aboriginal and Torres Strait Islanders, even though a lot had changed since the 1970s.

"Aboriginal and Torres Strait Islander people now have a seat at the table - in governments, boardrooms and at the top of the public service," he told AAP.

"I find that achieving better outcomes for Indigenous Australians works better from the inside, rather than the outside of the Australian democratic system."

Australian Associated Press