A fast logistical catamaran has the added advantage of being able to loiter in an operational area off shore. With air transport, you send them or you don't. There is no holding them in internaional water, but ready and close by.
Of course, that presupposes the Kiwis had a navy to protect that fast logistics ship....
The NZ Navy is currently tendering for a new transport/logistics ship to be available 2005