Nut lovers look out - Whittaker's is cutting one of its blocks.

Nut lovers have a couple of weeks to stock up on Whittaker's macadamia blocks as the company cuts the product in the face of global macadamia turmoil.

On Tuesday, marketing manager Holly Whittaker said the block would be available for the next "two to four weeks" in supermarkets, depending on stocks.

She said the Porirua-based Whittaker's sourced "commercial quantities" of its macadamias from Australia, with demand outstripping supply for several years, which pushed up prices.

"We've absorbed the increased prices for macadamias for some time, but can no longer continue to do so, especially given the outlook for macadamia demand and supply."

Whittaker's had decided to let people know "as soon as possible" so they could stock up.

Topnotch Orchards operations manager Carl Murphy said major storms in the 2013-2014 growing season in Australia had hit worldwide production hard.

The Australian macadamia industry was the world's largest producer, with about 60 per cent of its yield exported to the world market.

Murphy said Topnotch, which grows and processes the nut near Morrinsville, faced such high demand that it had been forced to buy in product from other growers in New Zealand.

He was "quite blown away" by the Whittaker's news and had even approached the company himself about 18 months ago to see if Topnotch could become a supplier.

"Now I simply cannot grow enough to supply our current local demand, let alone what's going on overseas."

New Zealand imports about 300 to 400 tonnes of macadamias a year from Australia alone, he said.

Whittaker said the end may not be a permanent one for the macadamia block in New Zealand.

"For now we can't put a timeframe on the deletion. If the market does stabilise of course we will look to reintroduce the block to the range."