Central District road policing manager Inspector Dave White said winter provided challenging driving conditions including snow and black ice on roads.
He said there were a number of crashes in the district this morning from black ice, "so I want to remind drivers that they need to be alert and adapt their driving.''
Snow and ice yesterday closed a number of highways across the country, but they had all reopened today.
Meanwhile, police were warning drivers they would be on the lookout for speeding vehicles over Queen's Birthday weekend.
For the duration of the Queen's Birthday holiday period, the speed limit tolerance was 4km for all permanent posted speed limits.
Central District police would also use a plane for the long weekend to monitor traffic flow and identify speeding vehicles.
"Along with the aircraft, our officers will be out keeping the roads safe and anyone we identify doing anything that places other drivers at risk can expect to be caught,'' Mr White said.
Queen's Birthday weekend officially starts at 4pm on Friday and ends at 6am on Tuesday.
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Police cold weather driving tips:
* watch speed and following distance;
* take a break if tired;
* always buckle up;
* plan the journey; and
* check the latest weather and traffic updates.