Paul Nicholas Schild, 50, pleaded guilty in the Launceston Magistrates Court on Wednesday to one count of driving a motor vehicle while exceeding the blood-alcohol limit.

A member of the public alerted police to a driver swerving for several kilometres on the Midland Highway south of the Kings Meadows Connector with a flat tyre about 10am on November 6.

When pulled over by police and breath tested, Mr Schild told officers he only had "a few swigs of whisky" at 8pm the night before and thought he was under the limit. He was driving "to get to work", he told police.

IN OTHER NEWS:

He gave a reading of 0.192, resulting in a mandatory disqualification of 12 months.

The court heard Mr Schild - the only pharmacist in Perth - believed he "must have awoken during the night and consumed further alcohol" because he could not find the bottle the following the morning.

When he awoke and realised he was late for work, he "went into auto pilot" and started to drive to Perth.

The court was told that Mr Schild was "incredibly embarrassed and remorseful".

It was the first time he had come before the courts.

Magistrate Sharon Cure said that Mr Schild must have drunk "a lot" to record the reading, but accepted his remorse.

"Even though it's a high reading, he is otherwise a respected member of the community," she said.

"Because at your age you've never been before the court ... I will impose the minimum."

Ms Cure said that Mr Schild "may have to address his alcohol use".

He was fined $860 and his licence remained disqualified for 12 months from the date of the offence.