Collectors have "scrambled" to nab coins commemorating milestones during the Queen's 70-year reign, clearing out the shelves of local coin dealers.

Newcastle Coins owner Shane McCulloch said demand and prices for some coins went "through the roof" on the morning the Queen died.

"I was inundated with orders I couldn't supply - I depleted all my stock," Mr McCulloch said.

Mr McCulloch, who has been in the coin industry for almost 25 years, said his business made over a month's worth of sales in the last five days through its website.

The Queen's Platinum Jubilee 50c piece was one of the most sought-after coins, he said.

"On the morning of her passing, the Platinum Jubilee 50c piece flew through the roof,"

The coin, usually stocked by the Royal Australian Mint for $12.50, was "regularly hitting" $100 for the uncirculated coin, and $400 or more for the proof coin, he said.

"I guess people are starting to scramble a bit for anything with the Queen's face on it," he said.

Coinworks Managing Director Belinda Downie said now that Elizabeth II coins are no longer "current", there has been a spike in demand.

Coinworks deal in coins struck prior to the decimal change in 1966, so Queen Elizabeth only features in that coinage between 1953 and 1964.

"What I have always noticed about our area of the market is that people would prefer George V and George VI because Elizabeth II was seen as current," Ms Downie said.

"Now that the monarch has passed, Elizabeth II coins are no longer current and there is definitely an increase in demand."

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Australians will see the face of King Charles III on coins in the future, but the process can be lengthy, Mr McCulloch said.

A Palace-approved effigy of the new sovereign is likely to be provided to the Royal Australian Mint by the UK Royal Mint.

"Historically, coins bearing a new sovereign's effigy were released approximately 12 months after coronation of the sovereign," according to the Royal Australian Mint.

The image of King Charles III's head will be facing the opposite way to Queen Elizabeth's in a tradition dating back to King Charles II in the 17^th century.

In the meantime, coins featuring the Queen will continue to be minted.