More people appear to be getting the message to lock their cars, but insurers are frustrated at an increasing tendency to leave valuables inside for smash-and-grab thieves.
AA Insurance is pleased that more than nine out of 10 participants in a survey of 1000 drivers said they always locked their cars.
A figure of 91 per cent for those security-conscious drivers was up six percentage points from the company's previous annual survey.
But the proportion who admitted leaving valuable items in unattended cars was also up - to 41 per cent from 38 per cent last year.
Young drivers were more inclined to throw caution to the wind, with 54 per cent of those aged 18 to 29 leaving possessions in cars.
That compared with just 23 per cent of those aged 60 or more.
Thieves appear to be thriving on their laxity, as AA Insurance is making more payouts for thefts from cars.
According to figures issued today, it says vehicle theft claims cost it about $1 million in the year to September 30, up from $810,000 for the previous 12 months.
Although average payouts ranging from $1000 to $1500 were down from $1700 last year, AA Insurance customer relations manage Amelia Macandrew said they still represented hefty and disappointing losses for the company and its customers.
"The items we regularly carry around with us can often add up to hundreds, if not thousands, of dollars," she said.
Ms Macandrew said the most commonly stolen items were clothes, makeup and handbags, followed by mobile phones, laptops and iPads.
Although thefts from vehicles were a year-round plague, they were particularly heart-breaking in the lead-up to Christmas "when you've spent time and money on gifts for friends and family."
"People sometimes leave their Christmas shopping in their vehicle while they look for a few more gifts, believing thieves wouldn't be so brazen as to break into a car in the daytime."
Travel items were also a popular target of thieves in the summer months.
An example cited by AA Insurance from last summer was a family which lost almost $3000 of belongings after returning home from a trip, and deciding to leave it until the following day before unpacking them.
That was despite the family's car being parked in its driveway, with the items hidden or left in the boot, only for a window to be smashed in by an opportunist thief.
Ms Macandrew said it would the nice if people showed more Christmas spirit.
"But it's often a case of opportunity for thieves who have their own style of Christmas shopping."
The company's survey findings come as Auckland police distribute yellow cards around city parking buildings and vehicle rental companies, urging drivers to remove valuable items from unattended vehicles.
Motorists are being urged to display the cards in car windows, declaring to thieves that there is nothing left inside to take, so no point in smashing their way in and causing needless damage.