Scott Graham said he found about 40 shells of abalone on Spring Creek Road, Bonny Hills. 

Scott believes they would have been taken from the rocks at Bonny Hills, as he said this is where they can be found in the region. 

Scott said majority of the abalone he found was undersize. 

The legal minimum length is 11.7cm and Scott said some of the shells found were not even nine centimetres long.

"I found this act disgusting as I am a fond recreational abalone diver myself," he said.  

Scott said the current bag limit for each fisherman is two per person per day. 

A spokesperson from NSW DPI said people are encouraged to contact the body with any reports of illegal fishing through Fishers Watch on 1800 043 536 or online at the DPI Fisheries website.

"A reward of up to $1250 may be available to anyone providing information leading to a conviction depending on the seriousness of the offence," she said. 

The spokesperson said the DPI Fisheries Compliance Unit has made inroads into addressing illegal, unreported, unregulated (IUU) fishing in the NSW abalone fishery.

"More than 5700 illegally taken abalone were seized during the 2017-18 financial year including the largest seizure of illegal abalone in 20 years," she said. 

Last financial year NSW DPI seized 2560 illegally harvested abalone.

"NSW DPI has seized more abalone from a number of alleged offenders this year and intend to take the offenders to court," the spokesperson said.