The speed limit can go up to 110km/h on some roads, the Government has announced - a change Labour fears could cost lives.
Associate Transport Minister Craig Foss has released a new "speed management guide" that will allow speed limits to be raised under some circumstances.
"Changes made under the guide may include altering road design, lowering speed limits, or in certain circumstances, raising them.
"To be eligible for a 110 km/h limit, a road will have to meet very strict conditions, including having a median barrier, at least two lanes in each direction and no direct access to neighbouring properties."
Foss said the guide would help councils, the New Zealand Transport Agency and other road controlling authorities decide where and when to make safety improvements or change speed limits.
Labour's police spokesman Stuart Nash said the research he had seen suggested raising the speed limit would lead to more road fatalities.
"I'd be interested in what the experts have to say...my gut feel is we have it about right at the moment.
"I think if you make it 110km/h, then 110km/h becomes the absolute new norm. But what happens in people's minds is they think, 110km/h is the limit, I can drive at 115km/h and get away with it," Nash said.
"They go onto a road where the speed limit is 100km/h and they are still travelling at 110km/h, because they are doing that for the past hour. I just think we are playing with fire, and we are playing with the lives of Kiwis."
However, Police Minister Judith Collins had no problem with the change.
"It is only on a few roads that are specifically engineered for this."
Foss said the higher speed limit would only be possible on about 150km of current roading, mostly state highways.
"Such as parts of the Waikato Expressway, the Tauranga Link, parts of the Northern Expressway in Christchurch, parts of Transmission Gully and the new Kapiti extension.
"Those types of highly-engineered, medium barrier, double lanes roads, it is possible that they could do 110km on them."
The speed management guide will replace the speed setting guidance in the Land Transport Rule: Setting of Speed Limits 2003. Consultation on the changes will begin early next year.
A 110km/h limit has been considered for some time for motorways built as part of the Government's roads of national significance programme.
"Speed limit reviews...currently do not give sufficient weight to road classification, design, geometric characteristics, network efficiency or the safe system approach," the new speed management guide states.
"The result is that on some routes, travel speeds are not appropriate to road use and function."
The guide was released after consultation with the Automobile Association (AA). The association has for a number of years advocated for a 110km/h limit on the safest roads, saying it could reduce congestion and improve productivity by ensuring the quicker movement of freight.