With only a mere handheld metal detector to use, an amateur Australian prospector has unearthed in Ballarat a huge gold nugget, believed to be weighing 5.5kg or 177 ounces, the value of which could reach a whopping A$300,000 ($315,000).

If sold at market value, it would be worth A$300,000, but because it is a rare find, its worth could be worth much more, Cordell Kent, owner of the Ballarat Mining Exchange Gold Shop, said.

The identity of the prospector who discovered the find remained unidentified man. What’s only certain was that he found the nugget on Wednesday, via a handheld metal detector, lying 60cm below the surface of the earth near the town of Ballarat in the state of Victoria, Australia.

But Mr Kent said the nugget was found within 30 kilometres of the Ballarat CBD. The detector used was a Minelab GPX-5000, a state-of-the-art detector worth $6,000 and above.

"I have been a prospector and dealer for two decades, and cannot remember the last time a nugget over 100 ounces (2.8kg) has been found locally," Mr Kent said.

The prospector, according to Mr Kent, had discovered gold before, but only small pieces, nothing worth more than $1,000.

"Up until yesterday, the smallest nugget he had found was a small one, about a quarter of an ounce," he said.

"I've got no doubt there will be a lot of people who will be very enthusiastic about the goldfields again, it gives people hope.”

"There's nothing like digging up money, it's good fun."

Gold currently trades in Australia at A$1,600 per ounce.