A Tasmanian motorist caught driving 45kph over the speed limit told police he had just washed his car and wanted to dry it.

The Hobart Magistrates Court heard Adam White was clocked at 125kph in an 80kph zone on the Brooker Highway near Hobart in April.

Magistrate Glen Hay told the father of two it was the strangest reason he had heard for driving while disqualified.

White was given a 28-day suspended jail sentence and a 12-month good behaviour bond.

He was disqualified from driving for 10 months and fined $900, and lost six demerit points.

Mr Hay told him it would have been cheaper to buy a couple of hairdryers.