A Masterton teenage driver tried to fool a roadside breath test on Saturday by gargling deodorant.

The 17-year-old told police he had sprayed Lynx into a glass before using the liquid "like mouthwash".

But the alcohol in the deodorant had the opposite effect, pushing him over the adult limit.

Police say his doomed "fix" was certainly unusual, but was nothing compared with other extreme measures taken by drunks, some of whom have eaten soap and faeces in attempts to beat the breathalyser.

Senior Sergeant Warwick Burr, of Masterton, said the teenager was pulled over for a random breath test in Lincoln Rd at 11.40pm.

An initial screening produced a reading of more than 400 micrograms of alcohol per litre of breath, and he was taken to the Masterton police station for an evidential test. A zero limit applies for drivers aged under 20; for adult drivers the limit is 400mcg.

The youth said he had drunk only two beers before gargling the deodorant. At the station, he was allowed to wash out his mouth before taking the evidential test.

That produced a reading of less than 150mcg - meaning he was able to avoid a drink-driving prosecution. As a youth driver with a reading below 150mcg, he was fined $200 and given demerit points, without having to appear in court.

Senior Sergeant Doug Rowan, of the Wellington District road policing group, said people tried to eat and drink "all sorts of things" to mask alcohol on their breath.

"We've seen people pulled over and they're guzzling water or Coca-Cola out of the bottle. You see it quite often."

Others had eaten soap at the police station - "literally making themselves sick".

He was even aware of some people "at the extreme end of things" resorting to "putting faeces in their mouths" at the police station in the hope it would fool the breathalyser.

"Drunk people do some funny things."

Alcohol-based cough medicine was also common, he said.

"People believe in their mind that the police constable will accept their story that they've got a cough and that the alcohol-based product is to blame.

"Ninety-nine per cent of the time, it's porkies."

Wellington lawyer Michael Bott said he had heard of many "tall tales" of efforts to mask alcohol, including taking lozenges, Gaviscon antacid, and putting copper coins in your mouth.

He said a client "of a nervous disposition" once failed a breath-test after taking the brandy-based Rescue Remedy to help face the police alcohol screening.

His advice was to ask police for a blood test if a driver genuinely believed such a substance was to blame for a skewed result.

The sample would detect the true alcohol content in the body, without being tricked by other substances on the breath.