South Australian MP Troy Bell will face trial for allegedly misappropriating $2 million of public funds.

Despite “mistakes and errors” in an ICAC probe on the matter, District Court Judge Liesl Chapman has refused to put the proceedings on hold.

However, she did find the Independent Commissioner Against Corruption (ICAC) exceeded its powers by continuing to investigate Mr Bell after he had been charged.

“I have found there was unlawful exercise of powers, however, that on its own is not sufficient for a stay,” she said.

“There were certainly mistakes and errors which were unhelpful.

“The conduct of the ICAC is not such that allowing the prosecution of Mr Bell to proceed would bring the administration of justice into disrepute.”

The independent Member for Mount Gambier has applied or his criminal prosecution to be put on hold indefinitely because he could not receive a fair trial.

Mr Bell has pleaded not guilty to 20 counts of theft and six counts of dishonesty.

He stands accused of misappropriating $2 million of education funding between 2009 and 2013 before he was elected as an MP. The charges related to the time the former teacher spent running an independent learning centre in Mount Gambier.

His lawyer, Marie Shaw QC, previously told the court that the ICAC had “interfered with the administration of justice” by working “arm in arm” with the DPP to prosecute her client.

Director of Public Prosecutions (DPP) Martin Hinton QC says Parliament tried to “tread that line between the protection of reputation and what's necessary to investigate corruption in public administration”.

Mr Hinton has conceded there was mistakes made by ICAC investigators during their probe into Mr Bell, but said it was not enough for his trial to be halted.