Tens of thousands of Australians protested over the treatment of Indigenous people on Sunday as the country celebrated a national holiday marking the 1788 arrival of British colonisers.

Two historic statues were damaged in Melbourne ahead of Australia Day celebrations on Sunday, with tens of thousands of people across the country joining protests in support of Aboriginal groups who say the date is not one to cheer.

Tens of thousands of Australian Indigenous activists protested over the treatment of Indigenous people on Sunday as the country celebrated a national holiday marking the 1788 arrival of British colonizers.

The dialling back of Indigenous rights will be high on the agenda for Invasion Day rallies this year, according to protest organisers who say it's a global "phenomenon" also happening to overseas colonised nations.