Charterboat skippers at Tutukaka hope the authorities will come down hard on a fishing boat they say was taking fish near the Poor Knights marine reserve.
Dive Tutukaka owner Jeroen Jongjens said skippers of his charter boat were among those that saw the crew fishing this week.
Mr Jongjens said the boat was a commercial one.
He said his crew double-checked the GPS location and found the vessel was well within the protected zone.
But when they tried to tell the crew, they denied it, and kept on hauling up long-lines full of fish and sharks.
Mr Jongjens said the charter-boat skippers took photos of the fishing-boat and its crew and sent them to the Ministry for Primary Industries along with a complaint.
The Ministry confirmed it was investigating the matter.
Exclusion zones around the Poor Knights vary, depending on who is fishing.
Recreational fishers must keep a distance of half a nautical mile from the islands; for longliners one mile and for trawlers 3 nautical miles.
People caught fishing in the reserve can be fined up to $100,000 and can forfeit their boats.