Only a quarter of the 20,000 "ravenous" kingfish that escaped from a fish farm off Port Stephens last month have been caught.
NSW Department of Primary Industries announced on Wednesday that the temporary closure of the waters in Huon Aquaculture's Providence Bay research lease would stand until February 28.
The controversial farm, jointly run by Huon and the state government, was destroyed in rough seas in late January, resulting in 20,000 kingfish escaping from "fortress" pens.
Marine Parks' Association chairman and whale watching tour operator Frank Future described the fish as "voracious feeders".
"From what I understand they are ravenous," Mr Future said last week.
"Once they realise they won't get any food in the form of pellets they'll be eating anything they can find. I don't want to think about the impact on wild species."
Huon Aquaculture has recovered 5000 fish so far. NSW Department of Primary Industries deputy director general fisheries Geoff Allan said recovery efforts were still taking place.
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"The closure was initially put in place due to the volume of boating traffic leading up to the long weekend, which created hazardous conditions within the research lease and hampered repair and fish recapture efforts," Dr Allan said.
"Despite advice, some fishers have been navigating too close to the mooring system and sea pen infrastructure, especially with divers in the water."
Findings on what caused the pens to break up will be released this week, the department said.
Breaches can lead to fines of up to $22,000 or six months in prison for a first offence.
Conservation groups and local tourism operators described the multimillion-dollar project as a "disaster" threatening the pristine marine park's delicate ecosystem.
Port Stephens MP Kate Washington queried the use of resources to protect the company's site as wild fish were at risk, labelling the response "last-minute" and "haphazard".
She said she would call for an "independent, arm's-length review" through parliament, flagging concerns that the freed fish would feed on baitfish, eating into commercial fishers' harvests.
"There's potentially an environmental disaster, there's potentially huge economic impacts on other people, meanwhile Fisheries are sitting out there protecting a catch that may or may not still be there," Ms Washington said.