Growers have just completed harvesting the Atherton Tablelands, Queensland's biggest potato production area.

Farmers averaged $300 a tonne, half of what they were expecting.

Wholesaler Paul Stadhams told abc News it will affect next year's crop. He said: "Compared with previous years that's pretty down. It will stifle a lot of people.

"It will certainly cut back a lot of capital investment which should happen, and it will make people think twice before they plant potatoes next year."