An Adelaide court has found Liberal senator Mary Jo Fisher guilty of assault but not guilty of shoplifting.

Magistrate Kym Boxall did not record a conviction, so the senator is assured of retaining her place in the Upper House of Federal Parliament.

Fisher faced charges after a visit to a supermarket in the Adelaide suburb of Frewville late last year.

She was accused of stealing $92 of groceries.

The court was told she repeatedly closed her car door on the arm of a security officer who followed her to the car park and tried to stop her.

The trial was told the MP was suffering from a panic attack, but a second medical expert called late in the proceedings questioned that defence.

Mr Boxall said he accepted Fisher's evidence that she had a panic attack in the store, but he was satisfied that she was conscious of what she was doing when she made physical contact with the security officer.

He said the assault was relatively minor.

The senator looked relaxed as the verdicts were given.

She was quick to get out her mobile phone and send a text message.

Mr Boxall ruled no conviction be recorded and no penalty imposed.

Fisher said outside the hearing the outcome was welcome.

"Confronting my health and dealing with a court case has been very challenging," she said.

"A huge thank you to my family, my friends, my staff, my legal team, my parliamentary colleagues across the political spectrum, many of whom have supported me.

"The decision is a very welcome relief."

The senator said she was pleased the magistrate found she had not acted dishonestly.

Opposition Leader Tony Abbott said his thoughts were with Fisher and her family.

He said the advice of the Clerk of the Senate was that she would face no disqualification from holding her place.

Fisher became a senator in 2007 when she filled a vacancy created by the retirement of former Howard government minister Amanda Vanstone.