Transport Minister Steven Joyce has conceded that reducing the legal blood-alcohol limit for drivers could save lives, prevent injuries and save millions of dollars in social costs.

But he said the Government's road safety package - announced Monday - already includes measures that will achieve the same ends, including a zero limit for repeat drink-drivers and drivers under 20.

The Ministry of Transport estimates that reducing the blood-alcohol limit to 0.05g and increasing public awareness and enforcement could save up to 33 lives, prevent up to 680 injuries and save between $111 million and $238 million every year.

"The reality is, there is a number of things we could do, and some of those things we're doing, and it's always a judgment in terms of which ones to do," Mr Joyce said.

"We looked at the ones that are going to make a difference and the level of public support."

The Government will keep the blood alcohol limit at 0.08g per 100ml of blood, rather than reduce it to 0.05g.

From next year it plans to do New Zealand-specific research for two years to see if many drivers with a blood-alcohol level between 0.05g and 0.08g are involved in many accidents.

"Transport officials feel strongly that it [lowering the limit] is an important thing to do, but of course politicians also have to judge the acceptability of measures to the wider public," Mr Joyce said.

Alcohol health groups have strongly criticised the decision, as have Labour and the Green Party.

Labour leader Phil Goff said there was enough evidence on the issue to warrant scrutiny from a select committee.

"There is no silver bullet for drinking issues. One of the issues in the mix needs to be to test whether the current limit is too high. It should go to the select committee.

"My personal preference would be to see it lowered on the basis of evidence that I've seen ... you need to drink an awful amount to reach that limit."

He said the research was an excuse to avoid it being an issue at next year's election. "That just puts it safely on the other side of the election. It's time to show some leadership."

Mr Joyce pointed out that Mr Goff was a member of the Labour Cabinet that left the blood-alcohol limit at 0.08g.

"It is interesting that it is such a hurry for them now when it wasn't a hurry for nine years."

Mr Joyce acknowledged the criticisms of public health groups.

"But there are significant gaps in our domestic research, particularly in relation to the number of people who have accidents between 0.05g and 0.08g."

* Hundreds of studies overseas point to the benefits of lowering the legal blood-alcohol limit from 0.08g to 0.05g per 100ml of blood.
* The Ministry of Transport estimates reducing it to 0.05g and increasing enforcement and public awareness could save up to 33 lives, prevent up to 680 injuries and save up to $238 million every year.
* The Government says there is a gap in domestic research and wants to gather data on drivers in accidents who have a blood-alcohol level of between 0.05g and 0.08g.