Timaru's Heartland Potato Chips is benefiting from the nationwide potato shortage in New Zealand.

The shortage has seen some stores, including Pak 'n Save Timaru, hang signs on shelves stating potato supplies are down and therefore some chip brands may not be available.

Heartland's owner Raymond Bowan was quick to respond when asked if his company had benefited from the shortage.

"Yes we would've definitely, we're selling more than we ever have before," he said.

The company's supply had remained chipper, which meant retailers, short on stock from other brands, had come calling.

"We're not struggling [with the shortage], we've had to work longer.

"We're on double shifts at the factory at the moment," Bowan said.

The company had 15 fulltime staff, with six working on the conveyor built at once.

Bowan said the factory was closing as late as midnight, whereas usually the conveyor belt would stop operating at about 4pm.

Heartland is producing around 1400 boxes of chips per shift, with 12 bags in each. The company has taken on extra staff to cope with the high levels of demand.

Bowan grows his own potatoes at Fallgate Farm in Orari.

Heartland's national sales manager, Brian Kirby, said the company had survived the national shortage partly because it was self sufficient.

"Absolutely, we're benefiting from Heartland being owned by a farmer who farms potatoes," he said.

Kirby said the company, which sells its chips in all Countdown and New World supermarkets and "90 to 95 per cent" of Pak 'n Save supermarkets, had benefited from what he called a "vacuum" effect. "It [extra demand] is good for us given we never had a shortage. But this has just created a real vacuum," he said.

Earlier this month another local company, Makikihi Fries, said it would start using locally grown potatoes again in February.

Company manager Greg Hayman said the shortage had stretched supplies, forcing the company to source agria potatoes from the North Island.