The name change for the holiday follows the death of Queen Elizabeth II in September 2022 and may require some adjusting after seven decades.

But the King's Birthday is not a national public holiday in Australia and varies across states and territories.

NSW, Victoria, Northern Territory, South Australia and Tasmania all hold the public holiday on the second Monday in June.

The ACT also follows this tradition but calls the holiday Sovereign's Birthday.

This year in Queensland the King's Birthday public holiday is on October 2 while Western Australia will mark the day on September 25.

WA had already made the switch to the King's Birthday public holiday in 2022 due to it falling after the Queen's death.

None of these dates actually fall on the birthday of King Charles III, who will celebrate his 75th on November 14, 2023.

The June 12 date aligns with the UK's annual celebration of the monarch's birthday on the second weekend of June.

Unlike Good Friday, Christmas Day and Anzac Day, the King's Birthday isn't a restricted trading day.

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This means there won't be the widespread shop closures seen on recent public holidays.

On June 12 many stores will operate as usual but individual businesses may choose reduced trading hours or to close altogether.

For AFL fans the public holiday has in recent years become synonymous with the Big Freeze match between Collingwood and Melbourne.

The event is a fundraiser for Fight MND's efforts to find a cure for motor neurone disease.

Former AFL coach and player Neale Daniher is the face of the campaign following his 2013 diagnosis.

In its ninth year the event has drawn stars including actor Eric Bana and surfer Mick Fanning to slide into icy waters at the MCG before the AFL match kicks off.

Coverage of the event begins on Channel 7 at 2pm.

It's also one of the last chances to catch Vivid Sydney, which ends on June 17.

The huge festival transforms the city with light displays and events including live shows and food experiences.