South Australia will extend a moratorium on genetically modified crops until at least 2019.

SA is the only mainland state maintaining a ban on GM crop production and trials.

Government Minister Leon Bignell said the state's GM-free status gave primary producers a competitive advantage in key overseas markets, including Japan.

He said a continuing ban would help protect premium food and wine production and allow grain producers to attract higher prices.

"We've got a strong reputation not just around Australia but around the world for producing clean, green premium food and we think having a moratorium on the growing of GM crops really helps us in that end," he said.

"People are paying a $50 a tonne premium and we think there's a lot more advantages to having the moratorium in place than to lift it."

The Opposition said it too would ensure there was a ban on genetically modified crops until at least 2019 if it took office next March.

But Opposition agriculture spokesman David Ridgway said a ban needed regular review to ensure restrictions on growing GM crops did not put local farmers at a disadvantage.

"We support a moratorium but it needs to be monitored," he said.

"The Government claims that we get benefits, more dollars per tonne, it enhances our reputation - it should be continually monitored just to make sure our farmers and our producers are getting the benefits the Government claims that we are getting a market advantage for our quality food and wine."

Fruit fly research boost

South Australia will step up its research efforts to remain free of fruit fly.

Premier Jay Weatherill said a $3 million research and development facility would be set up over the next two years at Port Augusta.

Researchers will develop male-only sterile Queensland fruit flies.

Those sterile males, or Q-flies, will be used to eradicate outbreaks interstate where the pest is endemic in many regions and in South Australia if isolated outbreaks happen.

"Sterile insects have been used with great success here and around the world but this will be a first for Q-flies," Mr Weatherill said.

"It will transform the way we manage fruit fly here and interstate."

Research and development organisations such as Plant and Food Research Australia will contribute $15 million to the project over five years.