Doubt you will find a liquidator in NZ because your retail market is structured different to that of the US, with most overstocks and such being sold off in sale type situations.
Liquidated stock becoming available due to foreclosures and such is usually sold off at auction, so you can certainly keep an eye out for any local auction houses that deal with foreclosures.
If you do find your way to a liquidation auction, take a full wallet because you may just be able to cash in. I often frequent liquidation auctions in Aus, when they become available, and you can do really well if you are cashed up.
When you do settle on a product you want to focus on, you can also try approaching manufactures, wholesalers and retailers in the industry, and see if you can deal directly with them to source overstocks and such, but you may need a substantial budget to back you up.
As far as a wholesaler, you really need to know what you want to source before you can even start looking for a wholesaler, because you will need to find a wholesaler that services the industry that covers the product/s you want to sell.
One important factor to consider is if you are looking at selling through online sites such as ebay, wholesale price may not cut it as most prices on these types of sites are already set at wholesale value, and below.
Makes it hard to get a sale when people are selling the same products as you, and selling them at the price you are buying through wholesale.