Environment Canterbury has investigated reports of smoke being seen and smelt across the southern side of Christchurch on Tuesday.

Residents contacted chrislynchmedia.com after noticing a strong smell of smoke in suburbs including Halswell and Waltham.

A teacher in Waltham said they made the decision to keep students inside the classroom due to the strength of the smoke smell.

An Environment Canterbury spokesperson told chrislynchmedia.com that officers were investigating in an effort to locate the source.

At 1pm, the organisation had received three complaints.

“Air quality indicators — measured at our monitoring site in Woolston — were slightly elevated, but not at a level for concern,” the spokesperson said.

They added that outdoor burning is not permitted on properties smaller than two hectares (20,000 square metres), even in rural areas.

“If outdoor burning is causing a nuisance, we encourage people to call 0800 765 588, 24 hours a day, or log it through Snap Send Solve.”

Fire and Emergency NZ communications shift manager Lyn Crosson said crews from Spreydon had investigated areas around the Port Hills but found no signs of any uncontrolled fire activity.

She said a combination of fog and cool morning conditions may have caused smoke to linger closer to ground level.