Police in New Zealand burning off seized cannabis were left red-faced when a change in the wind sent smoke billowing over a primary school, it was reported Tuesday.

Officers in the South Island town of Picton were destroying cannabis and shredded paper in an incinerator at the local police station when the incident occurred, the Marlborough Express newspaper reported.

It said St Joseph's School principal Peter Knowles noticed the smoke on Friday morning and complained to police, who immediately extinguished the fire.

Senior Sergeant Peter Payne said a small amount of cannabis was in the incinerator when the wind changed direction and unexpectedly took the smoke over the school.

"A big gust just came and took it in a different direction. It can't be helped, it's just an act of nature," he told the newspaper.