WA Premier Colin Barnett says he is "extremely disappointed" by the City of Fremantle's decision to axe its Australia Day celebrations.

Fremantle has abandoned its Australia Day festivities in favour of what it describes as a culturally inclusive alternative celebration two days later.

The council voted in January to can its Australia Day fireworks display and replace it with a new event, called One Day.

It said it wanted to celebrate being Australian in a way that included all Australians, and believed moving away from the January 26 date was more in line with Fremantle's values.

Mr Barnett has made it clear he does not support the move.

"I am extremely disappointed in the Mayor and the City of Fremantle for doing that," he said.

"It's disloyal to our country, it's disloyal to our state, and I think it's disloyal to the community of Fremantle.

"There are people from all over the world who live in Fremantle and we come together as one people, one country on Australia Day — no one should undermine that.

"Everyone understands the history and the debate about Australia Day but Australia Day is our national day, most Aboriginal groups accept it and history is put to one side.

"Australia Day is now a day for all Australians — whatever their background, wherever they were born — and I think any group that tries to detract from that does a disservice to our country and to our people, all of our people."

The City of Fremantle has previously said the move has the support of Aboriginal people in the Fremantle area and denies the council is trying to be politically correct.