An increasing number of boat skippers are breaching maritime laws and illegally entering the Poor Knights Islands Marine Reserve on Northland's east coast.
Nineteen infringement notices relating to the area were issued by Maritime NZ last year compared to five in 2016 and 10 in 2015. The notices also incurred fines of between $2000 and $12,000.
Most of the offenders were operators of visiting cargo ships navigating a direct line down the east coast of Northland to save time and cost — coming between the Poor Knights and the mainland, rather than diverting around the reserve, specialist investigator Nick Dowden said.
The high-status reserve is one of only two in New Zealand waters where large boats are not allowed. The other, also in Northland, is the Three Kings Islands Marine Reserve, 55km northwest of Cape Reinga.
Fishing from any boat is prohibited in the Poor Knights reserve and ships longer than 45 metres banned from the designated "area to be avoided".
The marine reserve is a mecca for divers and nature buffs with its sea caves and rock stacks, abundant fish and shellfish species. It has been touted as one of the world's top dive locations and is a major attraction in the thriving Tutukaka Coast tourism brand.
''We want ship operators, masters and navigators to understand that this area is protected for a reason, and we take transgressions against the environment very seriously,'' Mr Dowden said.
The Maritime Operations Centre actively monitors the almost 80km-long area between Bay of Islands and Whangarei, which extends up to 35km off the east coast.
A digital geo-fence alerts the centre to ships entering the reserve and no-go area. Crews are then contacted by maritime radio and instructed the ship must leave by the shortest and safest route.
''As the regulator for the maritime sector, we are responsible for helping keep our seas safe, secure and clean, and we will take compliance action if need be," Mr Dowden said.
Maritime NZ data shows commercial ships are more likely to enter the Poor Knights banned area than the Three Kings Islands Marine Reserve, he said.
''Breaches can land the operator of the vessel with a $12,000 fine and the master can be fined $2000."