Following in the footsteps of fashionistas like Kate Moss and Jennifer Aniston and wearing sheepskin boots all day could be harming your feet.
As winter kicks in, podiatrists are warning about flat feet which can cause pain while walking and even standing.
Prolonged wearing of the boots, originally designed as indoorwear, can cause damage to the foot arch because of lack of support from the boots, they warn.
Bruce Baxter, of Foot Clinic Podiatry Med, said: "They're evil. It's not just the lack of stability, also in older people there is the risk of catching and tripping."
He said boot-style slippers compromise foot posture. In winter people reach for the boots because the sheepskin made them seem warm.
But he said a slipper's warmth depends on the thickness of the sole, not the lining of the upper.
A slip-on moccasin-style shoe with a sturdy sole was a better option for around home, he said.
Podiatry NZ spokeswoman Caron Orelowitz agreed, saying: "They are not doing your feet any good. They are also hideous and ugly, and apart from the fact they smell because people don't wash them, there is no support in them.
"Wearing them as shoes is not what the product is for. They are expensive slippers but they were not designed as footwear other than slippers."
Baxter said his clients who wore the boots for several hours each night were compromising their rehab from leg injuries because the boot's design often increased the vulnerability of a wearer's feet to stress as they moved around.
Even people who exercised in cutting-edge trainers would sometimes have injuries that lingered because of wearing inappropriate footwear.
Kiwis who had no previous foot problems also risked causing damage from wearing the boots as casualwear.
ACC statistics show there were 11,505 claims in 2014 for injuries relating to footwear, costing $5.9 million.
Figures could not be broken down to those wearing boots.
Ugg Australia, manufacturer of the world-famous Ugg Boot, did not respond to requests for comment.