Flooding has destroyed crops in three key food growing regions of Queensland and John Cummings from the National Association of Retail Grocers says WA growers will struggle to meet national demand.

Mr Cummings says pumpkin prices have more than doubled this week and he is expecting more pressure on the prices of other fruit and vegetables. "Local tomatoes will be travelling over to Queensland so if we want to buy local tomatoes we've got to pay more for it because they can get a higher price in the eastern states," he said.

Prices for mangoes, bananas, tomatoes and capsicums are expected to cost four times their normal price within days. Mr Cummings expects the prices to remain high for months while farmers come to grips with the damage. "It's a 10 to 20 billion dollar industry that we're talking about here and a big section of that has been wiped out. Fruits like apples and oranges are unlikely to be affected.