Police say they are disappointed the Labour Weekend road toll is already at two deaths and are calling on motorists to reduce speed and drive to the conditions.
Two people have died in separate crashes between cars and trucks in Dairy Flat, north of Auckland, and Lichfield in Waikato.
A speed tolerance threshold of 104km/h is in place for the weekend.
The country's national manager of road policing, Superintendent Carey Griffiths, said the lower threshold lowers deaths over time.
"The number of deaths over Labour Weekend varies dramatically. In 2012, it was six; 2011, it was eight. So being down at the one or two mark is an improvement but it's still two deaths too many."
Superintendent Griffiths said holiday road tolls will go down when people improve their driving year round.
Bad weather ahead
Bad weather is forecast in some areas for tomorrow's holiday weekend return drive.
Forecasters have issued a severe weather watch for Nelson and the lower half of the North Island.
MetService said there would be up to gale force northwesterlies followed by heavy rain.