Certainly seems so. According to Yahoo, James Cameron has bought 2 parcels of land totaling 2,470 acres of land in New Zealand a mere 12 miles from Peter Jackson's home. The purchase price is in the neighborhood of $16.7 million USD). Cameron's land lies 50 miles from Wellington.Records apparently show Cameron and his family residing there "indefinitely".
With news of his pending dives to the bottom of the world in the Pacific and as AVATAR 2 and 3 get closer to production it seems as though it is a good bet that the lion's share of production for the AVATAR sequels will be in Kiwi.
I'll ping my sources and check into things a bit more!