Up to 28 South Australian driving instructors have been red-flagged over allegations of fraud, inappropriate behaviour and failing to comply with regulations.

The number was revealed by the Department of Planning, Transport and Infrastructure, in the August edition of its Standards and Accreditations bulletin seen by the ABC.

Some of the issues include overcharging students, inappropriate behaviour towards students, failing to complete documentation and missing aspects of the main on-road driving test.

The department bulletin noted that six examiners had been suspended and ordered to undertake more training, while four received warnings, one had its licence revoked entirely, and "a number of matters are still open to investigation".

David Whomes, vice-president of the Professional Driver Trainers Association, said there appeared to be a number of "bad eggs" in the profession.

"If there's ability to make money, people will short cut it and put the dollar in front," Mr Whomes.

"There needs to be checks and balances to keep everyone honest."

Mr Whomes said in some cases, driving instructors were taking students out to lessons, even though they were not accredited to assess driving tests.

He said there were few auditors in the department overseeing drivers' licences, and people taking tests were reluctant to complain.

"The auditors should come from the industry and make sure they are well trained and aware of what the industry is doing," Mr Whomes said.

The RAA's Ben Haythorpe said more oversight of driving instructors was needed.

"An option that could be considered is equipping vehicles with cameras, which would provide an accurate record of all driving lessons and tests," he said.

"Parents expect their children to be taught how to drive at a high standard, and one way to ensure this is to make sure driving instructors and examiners are accountable for the lessons and tests they undertake."

The Department of Planning, Transport and Infrastructure has been contacted for comment.