The closure will allow samples of the paralytic shellfish toxin to be taken and tested. The toxins were found in samples tested from the Great Oyster Bay area and Norfolk Bay last week, with authorities saying they posed a serious health risk if eaten.

Waters targeted for closure are all waters within Great Oyster Bay and between the northern end of Wineglass Bay and the southern end of Marion Bay.

Primary Industries, Parks, Water and Environments's Robert Gott said the fisheries would remain closed until results indicated they could be reopened. "This will ensure no lobster from the biotoxin zone area enter the chain of supply," he said.

"Fishers must pull their rock lobster pots before midnight on Sunday, July 13, to comply with the closure which is effective from 00.01am on Monday, July 14."

For more information call the public health hotline on 1800671738.