A speeding driver's body would "disintegrate" and have to be picked piece-by-piece off the tarmac if he crashed while travelling 171kmh, a Hamilton magistrate says.

Alan John Caulfield, 59, received a dressing down and a $1300 fine when he appeared in the Hamilton District Court on a charge of dangerous driving on Wednesday morning.

Photo: File.

A police traffic patrol caught Caulfield's Holden on the Waikato Expressway near Horotiu driving 171kmh through heavy traffic.

The patrol car was travelling in the opposite lane and was unable to immediately catch up to Caulfield's vehicle, however he was eventually tracked down and charged.

Caulfield's counsel Shayne Lawry said he had not deliberately evaded the police at any stage and, at the time he was clocked doing 171kmh, had been "paying attention to the road, but not his speedo".

That explanation found little favour with community magistrate Kathryn Wilson who told Caulfield an error of judgement would have had dire consequences.

"At that speed your body would disintegrate and people would have to pick bits of you off the road," she said.

Wilson fined Caulfield $1300, with $130 court costs, and disqualified him from driving for nine months.