Two more cases of people being awarded high-paying executive positions based on fake qualifications have been uncovered after an urgent inquiry by the South Australia Government.

Last week, it was revealed the Government's recently appointed chief information officer, Veronica Theriault, had been sacked and charged with dishonesty offences, for allegedly using a fake resume to get the job.

Another public servant, Alan Corkhill, was also arrested last week and charged with deception and aiding and abetting Theriault.

Following the arrests, Premier Jay Weatherill called for an urgent review of the recruitment process.

The investigation uncovered two cases of alleged fraud from 2011, both within the shared services section of the Premier and Cabinet's Department.

The department's chief executive, Don Russell, said a man was appointed director of strategic programs, but later resigned amid allegations he had dishonestly represented his work history and academic qualifications.

New protocols introduced after cases emerge

In the second case, a former business engineering manager was fired during his probation period due to "unsatisfactory performance and incorrect statements made in connection with his application for employment".

"In this case, the former manager submitted a certified copy of his qualifications which was accepted then on face value," Mr Russell said.

"When later scrutinised, these qualifications and the copy submitted were proven to be false.

"It is clear to me that there have been some failings in the verification and checks on senior appointments."

Mr Russell said he had introduced new protocols which would take immediate effect for senior appointments.

These include detailed police and security checks, increased verification of work history and a "forensic investigation" of candidates' social media profiles.

Opposition spokesman Rob Lucas said the cases showed there was a long-running problem with the culture in the department.

"We've seen a long history of appointments being made, some without due process, that is without being based on merit-based selection and going to advertisement," he said.

"We've clearly seen even some of those where there has been a panel process used where due diligence hasn't been applied in relation to checking the references and referees."