Listen: John Wilson - Latest GDT result, 'a wee bit of a blip'

Dairy product prices fell at the Global Dairy Trade auction, as whole milk powder slid amid higher-than-anticipated supply.

The GDT price index fell 1.3 per cent and while whole milk powder retreated 1.1 per cent.

Fonterra chairman John Wilson spoke to The Country's Jamie Mackay, saying farmers shouldn't be concerned as the result is a "wee bit of a blip."

"We expected to see prices ... holding at the levels they are, they're going to bounce up and down a bit," says Wilson.

There have been suggestions that there is a "raid" on Westland Milk Products, with Fonterra trying to poach WMP farmers says Mackay.

Wilson dismisses this, saying that it's part of the "regulations that Fonterra must operate in."

"Within most parts of New Zealand we have to pick up milk. So when we get farmers that are interested in supplying Fonterra, as we have from some parts of the Westland region at the moment, we have to go and talk to them. But the right answer from my perspective, is to have a strong Westland."