ORC manager compliance Tami Sargeant said the council had dealt with a spate of potentially toxic fires this year.
Mattresses, plastic bottles, tyres, chemicals and waste oil had been burnt outdoors in Otago, she said.
"It’s important to think about what you’re burning; you’ll breathe it in and so will your family and your neighbours."
The best option was to find a way to recycle or re-use unwanted items or dispose of them appropriately at landfill, Ms Sargeant said.
"You can still have fires, but what we are saying is, please be up to speed with our rules and understand what you can and can’t burn."
ORC has produced a guide to rules around outdoor burning in Otago, aimed to help anyone navigate which rules apply in which part of Otago.
The guide can be found at www.orc.govt.nz/air-plan
