District Court Judge Liesl Chapman made her decision on Thursday following an application from the director of public prosecutions.

Her decision has also pushed the trial off until February 2022, when Bell will potentially be campaigning ahead of the state election the following month.

"I am going to take a conservative, cautious and pragmatic approach to the applicable legal test," she said.

"I am not going to embark on the trial proper with director's office having made this application and to have it hang over the head of what is going to be a very lengthy trial by judge alone.

"I am going to recuse myself."

Last month the Full Court of the Supreme Court rejected Bell's arguments that he could not get a fair trial and that the proceedings should be permanently stayed.

But it found Judge Chapman had erred in finding that some methods used by SA's Independent Commissioner Against Corruption in investigating his case were unlawful.

She specifically had issues with a decision by the ICAC to refer the prosecution directly to the DPP and bypass police.

The Supreme Court found the corruption watchdog could take such action.

Bell is defending 20 theft and dishonesty charges related to hundreds of thousands of dollars.

The charges cover a period before he entered state parliament when he worked as an independent provider of educational programs.

Prosecutors have accused him of overcharging and falsifying invoices, accounts and meeting minutes.

The 47-year-old has consistently denied the allegations.

As the member for Mt Gambier, Bell was first elected as a Liberal in 2014, but quit the party after his arrest in August 2017.

He was returned to parliament at the 2018 state election after contesting the poll as an independent.

Australian Associated Press