SYDNEY (AFP) - The date of Australia's national day should not be changed, the prime minister said Thursday (Jan 26), as thousands protested over the day that commemorates the arrival of the country's first British settlers.

While a national day of celebration, some Australians view the date as 'Invasion Day' as it marks the beginning of British colonisation.

"I believe we should maintain the date," Prime Minister Malcolm Turnbull told reporters in Canberra.

"Everyone is entitled to a point of view, but I think most Australians accept Jan 26 as Australia Day," he said.

"It is a day where we celebrate the rich diversity of all of our cultures - from our First Australians... to the new citizens, migrants who come from such diverse range of countries."

There were several 'Invasion Day' rallies across major Australian cities, with protesters marching in support of the disadvantaged Aboriginal community and a change of date.

Deputy Prime Minister Barnaby Joyce told the Australian Broadcasting Corporation it was political correctness "out of control".

But former minister Ian Macfarlane said the date should be changed.

"I believe that all Australians celebrating our great country on a date not associated with past wrongs can only bring us closer," he wrote in a column for The Australian.

The west Australian city of Fremantle has rescheduled its formal events to Jan 28, with the city government stating the alternate date is more culturally inclusive.