As the State Government looks for ways to divert more of the wasted bananas into processed foods, growers have blamed the major supermarket chains for rejecting fruit that is too small or has superficial blemishes.

Primary Industries Minister Tim Mulherin said millions of bananas - nearly a third of the total crop - were graded out in the packaging process each year.

Australian Banana Growers' Council chief executive Tony Heidrich said yesterday he was disappointed at the wastage.

"Bananas that don't meet the grading overwhelmingly are put in a chopper and chopped into little pieces and are spread over the plantation as organic matter," he told brisbanetimes.com.au.

Mr Heidrich said the number of bananas that had to be destroyed had risen in recent years as the increasingly dominant supermarket chains were more demanding than traditional greengrocers.

"A greengrocer was more prepared to accept blemishes on the skin ... but the supermarket chains claim shoppers buy with their eyes and prefer their fruit and vegetables with as few blemishes as possible," he said.

"I think perhaps years ago when most Australians had some direct connection to somebody who had a farm, people understood farming was not an exact science and produce was not made in a factory."

Woolworths spokesman Benedict Brook said bananas remained one of the chain's top selling products because only high-quality specimens passed the grading standards.

"We've been in the business for 85 years now, we know what customers will buy and based on what history has told us, we give our growers specifications for fruit that will sell," he said.

"There's no point putting fruit on the shelves that won't sell."

Mr Brook said there was only "limited demand" for smaller, lunch-box size bananas so these products were not available at all stores.