Earlier this month Fisheries officers from the Far South Coast District and Special Operations and Investigations Group undertook a surveillance operation on a group of five divers at Lennards Island, in the Ben Boyd National Park.

Fisheries was assisted by officers from NSW Police and Australian Border Force.

All five divers were found to have committed fisheries offences, including possessing prohibited size fish, possessing more than the possession limit, taking fish using apparatus to breath underwater, and recreational fishing without paying a fishing fee.

A total of eight live abalone were seized, including six of prohibited size the DPI reported. They were returned to the sea a short time after seizure.

A total of $1900 in fines and five written cautions will be issued to the group.

"Fishers and divers are reminded that size and bag limits apply to many species in NSW. A current NSW Fishing Licence is required to be held by all non-exempt fishers/divers who take or attempt to take fish in NSW," Fisheries said.

"Only scallops and sea urchin can be taken by a person using an apparatus capable of supplying air to facilitate breathing underwater, such as SCUBA or Hookah.

"NSW recreational fishing rules differ to those of other states and territories."