Testing has helped the DPI nab offenders baiting with fillets of teraglin on a vessel off Evans Head along the state's north coast and could be used to target illegal fishing practices in the Macquarie River, DPI spokesman said.

The technology is tipped for use in a number of cases currently being prepared for the courts, the spokesperson said.

"In addition to the Evans Head incident, DNA testing has been used in Sydney and the NSW south coast on a number of occasions for evidential purposes to verify the suspicions of fisheries officers," the spokesperson said.

Carried out in the same way as human DNA testing, fisheries officers can have results back within four to six weeks.

While the costs can vary, local fishing expert Matt Hanson said it was well worth it the investment, and he looked forward to the technology being used at a local level.

"It's a really smart move," Mr Hanson said.

"Definitely we'd welcome anything that helps lighten the load of our two local fisheries officers."

Mr Hanson said the effort to restock the Macquarie River by community groups had seen a massive turnaround in replenishing fish populations in the past four to five years.

But said with plenty of known illegal fishing still going on, the use of DNA testing could prove to be the linchpin in prosecuting offenders.

"Anything that helps to stamp out illegal fishing practises that compromise the future of fishing for our children is most welcomed," he said.

The DPI said the latest technology highlights the need for transparency and honesty among anglers when dealing with fisheries officers.

"This case demonstrates officers will go to great lengths to enforce the rules in place to protect the marine resource in NSW," the spokesperson said.