An Auckland couple who clambered on to the Poor Knights Islands could now face prosecution by the Department of Conservation.
The department has also warned visitors to the reserve to stop feeding fish or face massive fines.
Over the holiday season, the rangers busted boaties flouting the rules in the
Whangarei Harbour and Poor Knights marine reserves.
The reserves are strictly "look - don't touch" zones.
DoC marine protection ranger Leon Candy said the Poor Knights Islands reserve was strictly no entry for people or dogs as several endangered seabird species lived there.
There were ground-nesting birds vulnerable to dogs and the islands were also home to tuatara and several species of endangered skink.
Just after New Year, a DoC ranger allegedly discovered an Auckland couple had landed on Archway Island - a popular dive spot near the Blue Mao Mao Arch.
The matter had been reported to the area manager for a decision on what enforcement action the department would take. Landing on the islands could lead to a $500 fine and one month in prison.
"The Poor Knights Islands and for that matter the Hen and Chickens and Bream Islands are all nature reserves. As such it is illegal to land on any of them without a permit issued by DoC," Mr Candy said.
"These permits are issued under strict supervision usually for the purposes of scientific work."
On New Year's Day, there were reports of people feeding fish within the reserve. The seemingly innocuous acts had the potential to quickly alter feeding patterns and make fish become reliant on being hand-fed.
A foreign yacht owner is being investigated after reports of illegal fishing at the Poor Knights.
Individuals prosecuted for feeding or catching fish at the reserve can be imprisoned for three months and fined up to $10,000. The boundary of the marine reserve is 800m out from the islands - which includes the Pinnacles and Sugar Loaf.
Mr Candy said the department had had excellent feedback from dive charter operators and private vessels in the area reporting illegal and suspicious activity around the Poor Knights.
To report illegal activity at the Islands call 0800 DOCHOT.
