Five of the six child pornography charges against former government minister Bernard Finnigan have been thrown out of a South Australian court.

Magistrate Simon Smart found there was no case to answer on five charges of taking steps to obtain access to child pornography.

But the Upper House MP will stand trial in the District Court on a charge of obtaining access to child pornography.

He is due to be arraigned in the District Court next month.

Michael Abbott QC told the Magistrate: "I advise the court that my client will plead not guilty and will preserve his defence."

Outside court Finnigan, 40, maintained he was not guilty of the alleged offence.

"I will vigorously defend that charge in the proper place, a court of law. Like anyone else I'm entitled to the presumption of innocence," he told reporters.

Bernard Finnigan became a Labor government minister last year, but is no longer a member of the ALP.

He remains in the Legislative Council and has been turning up to parliamentary sittings.