"Police are extremely disappointed in the road toll so far this holiday period. That means 12 families who we have had to break devastating news to. They now have to spend their holidays saying goodbye to a loved one," Mr Greally said.
He said it was significant a third of the fatalities so far have been motorcyclists.
"Every time you approach a car - or motorbike - with keys in your hands, you need to be aware that your decisions affect more than just yourself. You have to think about your passengers, other road users, your family and friends and the loved ones of other road users."
Yesterday two Whanganui motorcycle clubs - Ulysses and Triumph Riders - spoke about the high number of motorcycle accidents, pinpointing inattentive car drivers and inexperienced riders as common factors.
Both clubs recommended motorcycle riding training and refresher courses for riders of all skill levels and experience.
The article, published on the Chronicle's Facebook page, drew a number of comments suggesting both motorists and motorcyclists needed to take more care.
"People driving cars need to learn to actually look for bikes. I'm recovering from getting driven into, at an intersection. She pulled out from a side road, so I know how easily it happens ... open your eyes properly, car drivers," wrote Mel Smyth.
"Bikes also need to obey the road rules, both motorbikes and bicycles," Claire Edmonds responded.
Mr Greally said all holiday crashes were under investigation and it was too early to speculate on causes.
"But I can say with some confidence that they were all avoidable."
"I can't say it enough - watch your speed, your following distances and wear your seatbelts. Adjust your driving to the conditions - whether it's weather, the state of the road or the driving of other motorists.
"Above all, if you see any driving that causes you concern, don't hesitate to call *555. We will do something about it."
The official holiday period began at 4pm on Friday, December 23, and ends at 6am on Wednesday, January 4.
The most commonly cited contributing factors for crashes over the last Christmas holiday period included losing control (41 per cent), travelling too fast for conditions (27 per cent), alcohol or drugs (18 per cent), inattention (15 per cent), did not see other party (13 per cent) and failure to keep left (12 per cent).