The Dimplex 9L Desiccant Dehumidifer (GDDEKD9) is $333 at Harvey Norman ($399 elsewhere).

This is a new product which looks like it might be better than the Goldair GD330, the other dessicant dehumidifier available in NZ. It is a little smaller, has a 5l tank (c.f. 2l), extracts an additional 1L/day, indicates actual humidity level, has an air deflector to vent the air horizontally rather than directly upwards, has a carbon filter, and has a longer timer (1-24 hour). But it is a bit more expensive (sticker price and replacement filters) and is slightly heavier at 7.5kg.

Dessicant dehumidiers are rated for cold climates and work even at 0C unlike the more common condenser dehumidifiers that are rated for tropical climates (30C and 80% humdity) and are far less efficient at lower temperatures. See this Radio NZ/Consumer NZ article "Dehumidifiers: a buyer's guide"

(Edited to correct price elsewhere and add another article below)

Here's an easy to read article on the cost benefit of a dehumidifier http://www.iwilltry.org/b/heat-your-home-with-a-dehumidifier/