"Tragically, multiple families are now grieving their loved ones following five separate fatal crashes on our roads since Monday night," Greally said.
Aside from the Katikati crash, there have been fatal crashes in Northland, Tasman, Counties Manakau and Central Districts.
"While the causes of these crashes are still the subject of police investigation, we know that from past experience crashes like this are usually preventable, and to see yet more families left devastated in this way is incredibly sad.
"As far as police is concerned, any death or injury is one too many, and everyone needs to be doing their part to reduce deaths and injuries on our roads," he said.
"And with winter weather well and truly upon us - with yet more bad weather forecast over the coming days - drivers need to be extremely careful and make allowances for the conditions."
Greally advised motorists to allow extra time for their trips and to be aware of other road-users who may not be easily seen, such as cyclists, motorcyclists and pedestrians.
"We want everyone to be safe on our roads this winter, so please take care," Greally said.
