Bernie Connell is an oyster farmer from the Clyde River on the NSW Far South Coast hoping to claim a Guinness World Record at this year's Narooma Oyster Festival.

Mr Connell has been growing a Pacific oyster named Jack for the last four years. Incredibly, Jack the Oyster has grown to the size of a human forearm and unofficially weighs just over 2 kilograms.

The standout of the crop

Mr Connell said it was not uncommon for some oysters to grow at faster rates than others in a batch.

"Every batch of oysters you get, there's always a certain few that grow a lot faster than the other ones, so he [Jack] stood out for the last four years," Mr Connell said.

"Any time I'd come back and work my crop he'd be a lot bigger than the other ones.

A regular-sized Pacific oyster weighs 50 grams on average. ( ABC News: Ben Millington )

"After a couple of years he was pretty big … so I put him in his separate little home and he's just grown from there.

"He's still growing. Every time I pick him up he's got a fringe on him – new shells. So if nothing happens to him he should grow into a pretty big oyster," he said.

Mr Connell said there are several oysters on his lease which could break the record.

The Usain Bolt of oysters

Mr Connell said growing Jack has not meant much extra work, aside from finding the right spot in the river and a bit of tender loving care.

"They're just a special type of oyster, like Usain Bolt … Just a champion oyster," he said.

"Every couple of months I bring him back to the shed and clean all the barnacles and seaweed off him.

"They [the oysters] all eat the same sort of stuff … I look after them and they grow.

On whether Jack has reached his peak, Mr Connell said he has still got some growing years in him yet.

"He's only four years old and the one overseas [which currently holds the record], they reckon is about 16, so he's got a lot of growing to do," he said.

A world champion oyster

The current world record holder form Denmark was crowned in 2013 weighing 1.62kg. ( Supplied: Guinness World Records )

According to Guinness World Records, the current record for the largest oyster was set in Denmark in 2013 by another Pacific oyster found on the shores of the Wadden Sea.

The oyster had another five attached to it, but the cluster weighed a total of 1.62kg and measured 35.5cm long.

All new world record contenders looking to claim the official title will be weighed, measured and photographed at the Narooma Oyster Festival this weekend. The information will then be sent to the Guinness World Records office for an official appraisal.

And as for Jack the Oyster, it looks like he will avoid the plate.