Sergeant Paul Stanhope said a report was made by a member of the public to Hamilton police about 1am this morning about an erratic driver on the Hamilton Highway between Tarrington and Hamilton.

The caller said the driver was on the wrong side of the road and driving at a speed of about 60km/h in a 100km/h zone.

A divisional van crew intercepted the 91-year-old Hamilton driver who said he had been drinking whiskey.

He recorded an evidentiary breath test of .07.

The elderly driver will lose his licence for three months and then be required to have an alcohol interlock device on his car for six months.

Police are likely to request his ability to hold a licence be reviewed.

Sergeant Stanhope said Hamilton police had dealt with the full spectrum of drink-drivers in the past few days, ranging from the 91-year-old to an experienced driver accompanying a learner, who was also caught over the limit.

"We've had a couple of unusual ones, but the bottom line is that people who drink and drive will be caught and prosecuted to the full extent of the law," he said.

On Sunday Sergeant Mark Phillips said that after midnight Hamilton police routinely pulled over any cars they saw and conducted alcohol breath tests.