A single alcoholic drink triples a driver's risk of dying in a vehicle crash, and a small beer or glass of wine can increase a driver's blood-alcohol level by more than half the legal limit, a report has found.

The British report, commissioned by the Government, has advised that legal limits for drinking and driving should be reduced from 80mg of alcohol per 100ml of blood to 50mg.

The call mirrors that of reports in New Zealand. Last year, the Government proposed lowering the blood-alcohol limit from 80mg to 50mg - something backed by health experts and included as one of 153 recommendations in May's Law Commission report on reducing alcohol-related harms.

New Zealand and Britain have one of the highest legal limits in the world. Only south Cyprus has a higher limit, of 90mg.

The British study found even at the one-drink level, the chances of a fatal accident are three times higher than in a driver who has drunk no alcohol.

But that is half the risk of the drink-drive limit of 80mg, which increases the chances of a fatal crash by at least six times. In drivers just over the limit, at up to 100mg blood alcohol level, the risk is 11 times higher.

The exponential increase in the danger for drivers drinking relatively small amounts of alcohol is spelled out in a report by the British medical regulator, Nice.

The effects are particularly acute in young people. The young are "less experienced drivers, are immature and have a lower tolerance to alcohol than older people", the Nice report says. Young people aged 18 to 25 are more likely to die in road accidents than from any other cause.

Lowering the blood-alcohol limit to 50mg would bring New Zealand into line with other countries, including France, Germany, Italy and Spain.

Luxembourg, Switzerland, Malta and Ireland have the same limit as Britain, 80mg, though Ireland is in the process of reducing the level to 50mg.

In Estonia, Romania, Slovakia and the Czech Republic the limit is zero.

Mike Noon from the AA said he did not support the 80mg or 50mg alcohol levels, saying that those drivers who did drink often did so excessively.

"We're calling for a review. The problem in New Zealand is that a lot of drivers are excessively over the limit, not just by one or two drinks."

Of the 30,000-35,000 drivers a year caught over the limit, one third are nearly twice the limit.

Mr Noon said one in five caught would go on to drink-drive again.

When the 50mg limit was introduced in 15 countries in Europe it resulted in an 11.5 per cent drop in fatal drink-driving accidents involving 18 to 25-year-olds, the group at highest risk.

- INDEPENDENT, ADDITIONAL REPORTING: CAITLIN DUGGAN