Authorities are currently dealing with problems in nine areas across Adelaide as well as an outbreak in Renmark, in the state's Riverland.

In each case, an eradication program is in place which includes measures for the handling and use of fruit.

With school returning for the new year on Wednesday, families living in those affected areas were also asked not to pack fruit in lunches.

"One of the reasons why we've done very well in this state is because we have been fruit fly free for a very long period of time," Mr Marshall said.

"That provides some advantages to our growers but also gets us into markets that are denied to other states.

"We've got to get on top of this. We can't allow fruit fly to get further into our state.

"We've got to hit it hard."

Primary Industries Minister David Basham urged all people to do the right thing, especially those living in the affected areas.

"It only takes one piece of fruit to cause devastation to our horticulture industry and impact backyard growers," Mr Basham said.

"If you live, work or go to school in an affected area, home-grown fruit and fruiting vegetables must not be included in lunch boxes or otherwise moved around, they must be consumed at home.

"If you live in an affected area any shop-bought fruit and fruiting vegetables must also be kept secure when taken home - this means in a sealed bag or other container - and it must then remain at home."

Mr Basham said all available resources were being used to combat the outbreaks and protect the state's horticulture industry.

Australian Associated Press