The Minister of Transport, Steven Joyce, says more evidence is needed before the Government will consider lowering the general drink-driving limit.
This is despite advice from his own officials that it would save lives.
The Government supports introducing a nil-alcohol limit for repeat drink-drivers and young drivers - a bill to that end is currently before Parliament - but Mr Joyce says it would be hard to get political support for lowering the limit generally without proof that it would save lives.
Provisional data for 2010 shows alcohol was a factor in 33% of fatal crashes.
Under the proposed law changes, Mr Joyce says, police will be able to record the blood-alcohol level of people under the legal limit who are involved in crashes.
He says that will provide the evidence required for a re-evaluation of the drink-driving limit.
The minister says the drink-drive limit has been an emotional issue for years and it would be hard to drive through changes without a durable political consensus.
Road toll drop 'no cause for complacency'
Mr Joyce also says the drop in the road toll is no cause for complacency, even though the 2010 toll was the second lowest in 50 years.
The provisional toll for 2010 is 373, 12 fewer than in 2009, and the second lowest total in 50 years.
Mr Joyce says, however, that New Zealand still has more road deaths per capita than Australia, Ireland and Britain do, and the toll is still too high, especially among youth.
He says the Government is working hard to improve road safety by such measures as changing the driving age, introducing alcohol interlocks and setting the nil-alcohol limit for repeat drink-drivers and young drivers.
In the longer term, he says, making improvements to major highways will also help reduce crashes, but ultimately governments can only do so much.