In this scenario the UN has called upon navies to deal with pirates in the Indian Ocean. NZ needs to contribute.
Most people turn to piracy because war has destroyed their livelihood on land, their seas are being fished out by foreigners and all they have is a few boats and some guns. That said the victims of piracy are often no better off than the pirates themselves - mariners from poor countries working in bad conditions for little pay. The best solution to the piracy problem is a viable home state with viable industries. Unfortunately that isn't happening. The pirates are armed and quite literally hungry. Many are under pressure to deliver ships or cargoes from warlords who rule their homes and have the power of life and death over the pirate crews. They are desperate men for whom violence is the main currency of business. There is no alternative strategy but a threat of overwhelming violence.
The main vessel for the mission is the Damen Schelde LSV acting as a mother ship. The mother ship has four heavy machine gun weapon stations to deter attack. A range of 10,000nm and an endurance of 30+ days given it can carry 40 containers.
The landing craft are substituted by four
High speed Lomocean Design interceptors each with a Marine boarding team and armed with stabilised remote weapon station such as the SAAB Trackfire. The trackfire provides stabilised targeting of weapons ranging from MGs to AGLs. The pursuit boat cruises at 40 knots and sprints at 65 to a maximum range of 300 nautical miles. That's twice as fast as most pirate motor boats.
In addition the mother ship can operate two SH-2G Seasprites.
In short the vessel could quite easily monitor a 100nm radius.