can new zealand support itself agriculturally?

The majority of countries can support themselves but there is a sound economic readon for import and export, it fosters a sense of global community all over the world.

I would say definitely yes. It has enough good farmland, and a nice climate to do this relatively easily if it were forced to. At present, it uses up a LOT of land for producing animal feed and fodder - its a huge meat producer and consumer!! If meat consumption and export were cut back enough, it would be quite easy for New Zealand to be completely food self-sufficient.