The South Australian State Government has committed to invest $110 million to expand the Northern Adelaide Plains irrigated food production area, which would create 3700 jobs and add more than $500 million a year to the state's economy, if the Federal Government also comes to the table.

Premier Jay Weatherill, joined by Minister for agriculture, food and fisheries Leon Bignell, and the Minister for water Ian Hunter, announced that they had already submitted an application to the National Water Infrastructure Development Fund for an addition $46.5 million.

The money will be spent to deliver an additional 12 billion litres a year - a 60% increase, of recycled water suitable for agricultural use from the Bolivar Waste Water Treatment Plant, as well as used to help expand the state's irrigated agriculture industry.

According to the State Government, new infrastructure would be built to deliver this recycled water to industry, with capacity to increase to 20 billion litres a year as demand and access to markets grows.

Weatherill said the plains were already home to one of the largest covered vegetable cropping regions in Australia and deserved new investment to grow further. 

"We must invest in the region now to ensure the horticulture industry has access to the large volumes of affordable, high security water it needs to increase production," Weatherill told a media conference.

Weatherill adds that the Government had independent economic modelling showing that plan would result in the creation of thousands of jobs.

"It will create 3700 jobs in the Northern Adelaide Plains region, which will be hit by the closure of Holden's Elizabeth car manufacturing plant later this year.

"A big part of the answer, in terms of the future of jobs in the region, is the food industry - not only the growing of food, but also the manufacturing of food and the export of food.

"The world is demanding food from clean air, clean soil, clean water, and South Australia has an extraordinary reputation for our premium food."

The State Government will continue to work with proponents, industry groups and growers in the region to ensure a fair, equitable and transparent process, and determine how they can participate in the additional recycled water allocation - delivering the greatest benefit for the state.

The project would also reduce impacts on the environment by making better use of recycled wastewater.

The State Government applied for the extra funding last year and expects to receive a response by the middle of this year.

"The Federal Government had been a great partner with us up to this point and that we're very confident that this fund will grant this application," Weatherill said. 

The Northern Adelaide Irrigation Scheme is the result of a $2.5 million feasibility study, commissioned jointly by the South Australian and Federal governments, to test market demand.