Christchurch residents are being urged to call the Fire Service or Environment Canterbury if they smell gas.
A number of complaints have been lodged across the city this morning about the worrying smell.
Bromley School remains shut today after becoming concerned by the smell yesterday.
It's thought the toxic smell could be coming from contractors turning over compost in Maces Road.
Fire communications shift manager Riwai Grace says ECAN is looking into the situation and anyone who is worried should contact them immediately.