A PORT Macquarie oyster farmer had $15,000 of oysters and equipment stolen from a lease in Limeburners Creek at the weekend.

Gavin Pix, from Holiday Coast Oysters, fears the row of 300 oyster baskets taken from his lease could have been earmarked for sale to farmers in other rivers.

"It could be just vandalism. But why just pick one row? You would think they would cut a few of them."

The juvenile oysters were found intact late on Monday about 5km upstream from Mr Pix's lease.

"I find it very difficult to believe they made it that far up the river just drifting," he said.

"There's a lot of bends and twists in the river. I'm hoping they weren't towed up there and put there for retrieval later."

Mr Pix said it would have taken a mammoth effort to move the oyster baskets.

"You could tow it but it wouldn't have been easy," he said. "Just the sheer volume of them would mean you'd need a very large punt."

Mr Pix was "dumbfounded" to discover the theft about 10.30am on Monday.

"You don't lose 300 baskets just like that," he said. "Even in a flood you don't lose that many, you might lose one or two. I was suspicious straight away."

The oysters were being grown using a floating cultivation system in which 150 baskets are attached to both sides of a line.

Mr Pix said the rows were secured by four anchor lines attached to half-tonne concrete blocks.

"Someone had cut all four anchor lines about 1m below the surface of the water," he said.

The oyster farmer of 12 years will have to "run a new line" and send a diver down to re-attach the anchor ropes but will be able to continue growing the oysters.

"I'll probably lose three days this week," he said.

The matter has been referred to the Rural Crime Squad.

Chairm an of the NSW Farmers Oyster Committee Mark Bulley praised Port Macquarie police for its quick response to the incident.