I remember Peter Ritchie, a well known taxidermist, making a fiberglass replica from a broadbill swordfish that was washed up already dead on a Christchurch beach. I think it was in the early 1990s.
I think a good way to fish for them is on a lumo squid at night. Several guys in the old Canterbury Sport Fishing Club talked about mounting an all out attack to try and catch one off Kaikoura down towards Motanau. There have been reports of sightings on the surface in the area over the years. However there was, and likely still is, a lack of suitable large launches, and skippers, capable of fishing that area in deep water, far from shore, and at night.