Tens of thousands of protesters are expected to take to the streets for Invasion Day rallies, while others brave heatwave conditions to head to the beach or a BBQ to mark Australia Day.
Official commemorations begin with flag-raising ceremonies before some 20,600 people from 150 countries take the oath of citizenship.
Police have vowed to be out in force at both celebrations and demonstrations, with the national day coinciding with the Australian Open men’s final in Melbourne.
Invasion Day events will kick off with dawn ceremonies around Australia before rallies in major capital cities and regional centres.
Victoria Police said they had done “extensively planning” for Australia Day community events and rallies.
“We’re well-prepared for all major events and will have a highly visible presence throughout the entire CBD to ensure they can occur safely,” a spokesperson said.
NSW Police promised to use “proactive policing strategies” to ensure minimal impact to the community.
“The NSW Police Force recognises and supports the rights of individuals and groups to exercise their rights of free speech and peaceful assembly,” they said.
“The first priority for NSW Police is always the safety of the public.”
Pro-Palestine activists who usually rally in central Melbourne each Sunday have urged supporters to join the Invasion Day protest march, which will start at state parliament at before heading to Flinders Street Station.
Organisers say January 26, the anniversary of the arrival of the First Fleet in 1788, is not a day to celebrate.
In Sydney, protesters are gathering at Belmore Park in Haymarket while in ACT the event will take place at the Aboriginal Tent Embassy.
Activists in Hobart are also marching to state parliament, while other protests and cultural events are also being held in Brisbane, Perth, Adelaide and Darwin.
In Melbourne, a smaller unrelated pro-Australia Day rally is planned outside Melbourne Park which is the home of the Australian Open, however it’s not expected to cross over with other rallies and police say organisers have provided them with details about their plans.
AAP