If NZ was serious about becoming a regional power we would certainly need our air power squadrons back. I have had a look at the JAS-39 variant and it has good combat range and the other thing is we wouldnt need many of them to have a good air cover. I would say around 12-16 of them. The only thing with the Grppen is it has had some bad press recently due to 5 crashes. So whether its integrity is intact is another issue. The Grippen can carry a maritime strike weapon.
Fast jets with a decent maritime strike capability is what you need, even one squadron would do. Grippens a good chioce, just as long as it has a decent marritime strike weapon, Harpoon Block II perhaps. Apart from that some UAV's would be good to spot the incoming fleet and provide data for AShM launch.