Emergency services at the scene this morning. Photo: Louise Scott
Emergency services were notified around 9.30am after the incident, in the Cherry Blossom Ave vicinity.
A St John spokeswoman said one person was assessed at the scene but did not need to be taken to hospital.
A man at the scene said police were evacuating houses around a 300 metre perimeter.
"It's maybe 50 houses ... they're knocking on doors."
Other people had been told to stay inside.
A large cloud of grey-white gas was visible near a house, and firefighters in protective breathing gear could be seen hauling heavy-duty hoses.
The incident was resolved before midday.
- additional reporting NZME
