South Australia is set to extend its controversial ban on the growing of genetically-modified crops until 2025 after a bill put forward by the Greens passed the Upper House by a single vote.

The current ban will expire on September 1 in 2019 and was due to be debated later next year, but the Greens surprised the State Parliament with its motion to extend it for another 6 years.

The bill is also expected to pass the Lower House, and Greens leader Mark Parnell said when that happens the State's farmers will be the big winners.

"There are a lot of farmers in South Australia who are nervous about the (GM) technology, and what the marketing evidence shows is that there is a price premium for not growing GM crops," he said.

"In other words, the price that farmers get for their traditional canola is much higher."

Mr Parnell said the Government backed his bill last night in the Upper House and he hopes that will continue when the bill goes to the Lower House where the Government holds a slim majority.

Mr Parnell said it would be a mistake to let the current moratorium lapse without political intervention.

"There are a lot of farmers who want to grow GM crops, but there is an equal number who don't, and in fact the grain producers themselves admit that it's about 50-50 [support]," he said.

"That is why it is important to make sure that if any decision to change the status quo is to be made, it will be made by Parliament."

Government support for longer GM ban

South Australia is the only mainland state where it is illegal for farmers to grow GM crops and Tasmania has made the ban indefinite.

South Australia's shadow minister for agriculture, David Ridgeway, said the Government tried to amend the motion to extend the ban until 2028, but it failed.

"We knew that the Greens motion would be put to a vote yesterday, but very surprised that the Government wanted to take it further. They wanted to increase the moratorium until 2028," he said.

"We are very surprised that they were happy to support it when clearly we have had no review, we have had no check and balance to make sure it is the right thing to do for South Australian producers.

South Australian Premier Jay Weatherill is a strong and vocal supporter of the GM ban, and earlier in the year said he would not be pressured by the grains industry to scrap the ban.

"The truth is there are not a lot of votes out there in country South Australia for us, so in some ways we are free of the electoral imperatives about this," Mr Weatherill told the ABC's Landline program back in July.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 15 minutes 13 seconds 15 m GM Debate: Is it time for South Australia's GM ban to be lifted? ( Marty McCarthy )

The Liberal Party opposition has not committed to removing the ban either, but has promised to review the ban if elected in next year's state election.

Mr Ridgeway said it is disappointing that there has been no consultation done with industry before the decision to extend the mortarium until 2025 was made.

He said it shows the Government does not care about farmers.

"This is a classic example that there is this arrogant, out-of-touch approach from the Government," he said.

"We know that people want us to have a look at it and we know they want to have a review, just to quantify what the benefits are. Right now we are not going to have that."

Lobby says ban restricting growth

Lobby group Grain Producers SA said the ban is restricting the growth of their industry.

Chairman and Parilla farmer Wade Dabinett said it is an "unmitigated disaster", not just for the grains industry but for the whole state.

Opinions on GM in SA South Australians have had their say on the South Australian Country Hour Facebook page with a mixed bag of opinions. Sandy said: "Fantastic … at least people have a chance to come to their senses about genetically-modified crops before there is no going back. If people want to grow them there is elsewhere they can do it". Anthony described it as: "Just another handbrake on the industry". Luke said: "Again we fall further behind the Amish … GM technology is about reducing chemical inputs and increasing production. The science has been ignored, again".

"We have had a moratorium in place, which has seen us be put a decade behind the other states and we are the laughing stock of the grains industry for being such a nanny state," he said.

"I am fearful that in my lifetime I am going to see our industry slip two decades behind, and I am flabbergasted that we have a policy in place when there has been no public consultation."

Mr Dabinett said he does not understand how this topic is still being discussed in 2017.

"I am so miffed that we continue to see this issue being kicked around like a political football at the expense of a significant industry in terms of agriculture," he said.

"There is absolutely no reason why GM crops can't co-exist … they are doing so in all the other jurisdictions and yet the SA Government won't do the work to prove their policy."

He said politicians have been short sighted on this topic and it is not only the grains industry that is missing out.

"They keep talking about canola, but what about the apple growers in the Adelaide Hills who are competing with interstate growers?" he said.

"What about the potato producers? There is the omega-3 canola that can help reduce the reliance on fish stocks for fish oil.

"It is just so short-sighted to lock all of these industries out and we need to get together here and say this is absolutely enough."

Non-grains agriculture quiet

While the grains industry is very vocal in its opposition on the GM moratorium, the state's other agriculture industries remain relatively silent.

The main reason for that is that they do not really need to weigh in.

The only GM crops available to grow in Australia at the moment are cotton and canola, so for horticulture such as wine, livestock and seafood it does not matter if there is a ban or not.

Rob Kerin from Primary Producers SA said despite this there has been plenty of discussion at PPSA meetings on GM technology that could be available in the future.

"There is no doubt GM is going to play a much bigger role in horticulture, better shelf life for example, and it could hurt us if we haven't got access to those technologies," he said.

"To have no review or consultation is ludicrous.

"We are saying 'no' and penalising our growers, we are allowing GM food to be sold in our supermarkets all coming from interstate … we are being denied a technology that is taking the rest of Australia forward and we are not allowed to join in."

Mr Kerin says all the other industries, such as dairy and horticulture, are in support of lifting the GM ban, but there are questions from the wine industry.

"We had a discussion about six months ago and everyone around the table supported going to GM," Mr Kerin said.

"The wine industry and their marketers do have a different point of view and we acknowledge that. That is where the consultation and reviews are needed."