South Australian Premier Steven Marshall says he is still considering whether to have the state's fracking ban enshrined into law.

Mr. Marshall told ABC Radio his cabinet had already implemented the 10-year moratorium on fracking for natural gas in the state's south-east by issuing a direction to the public service.

"We made it on Monday and I wanted to come straight down here and assure the people of South Australia that we've been true to our word," he told ABC Radio.  "We didn't want to wait until Parliament resumed.  We've already issued an instruction."

The premier said he might try to prevent future governments from overturning the ban by not enshrining it into law.

"We'll consider that.  But my advice from the department is that the moratorium is already in place after we made that cabinet decision," he said.