King Charles first Australian coins in circulation

"We've sent out three and a half million of these new kingly coins," assistant minister for Treasury Andrew Leigh said.

The freshly-minted $1 will be "handy for sausage sizzles and useful for parking", he said.

Other coin denominations will be rolled out with King Charles' portrait based on demand from banks.

Currency bearing Queen Elizabeth II would continue to be legal tender, The Royal Australian Mint said.

"It is a big moment for many Australians. It'll be the first time that most of us have held in our hands an Australian coin with a king's face on it," Dr Leigh said to ABC Canberra on December 7.

"They'll be rolling into circulation alongside the 16 billion coins with the Queen on them, which have appeared since the beginning of decimal currency in 1966."

Numismatic enthusiasts will have the chance to buy King Charles collector and investment coins from early 2024.

"Whether you're one of those collectors who's standing outside the Mint waiting for the latest release or just somebody who has an amateur coin collection. It is a mark of change," Dr Leigh said.

The King is the second monarch to appear on Australian currency as dollars and cents were introduced a decade after Queen Elizabeth II was crowned.