Police Minister Anne Tolley said the high level of support for the lower speed tolerance was encouraging, and showed that New Zealanders were taking the message to slow down seriously.
"This is a special time of year when New Zealanders should be enjoying time with their families and friends and I don't want anyone to have to suffer the trauma of being told that a loved one has been killed on our roads," she said.
The minister pointed to the success of previous trials. During Queen's Birthday Weekend in 2010 and 2011, a reduced speed tolerance and greater police presence were believed to have contributed to a 25 per cent drop in fatalities and crash-related injuries compared to previous years.
"That means there is an average of 30 people alive today who can celebrate Christmas who might not otherwise have been," Mrs Tolley said.
Speed cameras across the country have been set to the lower tolerance level, which has been supported by a $350,000 marketing campaign funded by ACC.
Police were also introducing 28 brightly coloured highway patrol vehicles to increase police visibility.
The Automobile Association said that for the lower tolerance level to be successful it needed to be focused on trouble spots - not just motorways and passing lanes - and had to be combined with highly visible enforcement. The association said that if the change simply led to an increase in speeding tickets then it was a failure,
Ministry of Transport data showed that the proportion of New Zealanders speeding on the open road had reduced since records began 17 years ago. In 1996, the mean car speed was 102km/h and 56 per cent of drivers travelled more than 100km/h. In 2012, the mean speed was 95.6km/h and just 25 per cent of drivers exceeded the 100km/h limit.