Gasfitters say the Christchurch gas explosion is a reminder of the need to check for gas leaks before lighting any gas appliance.
Plumbers, Drainlayers and Gasfitters Association president Glen Burr says there are many possible ways in which gas could have leaked in the house that blew up in the Christchurch suburb of Northwood, where most streets have piped liquefied petroleum gas (LPG).
"You could have a nail in the pipe, or someone actually cut it - anything can cause it," he said.
"It could be a leaky valve. It could be all sorts of things. It's too early to determine that."
But he said the explosion was a warning to be careful with all gas appliances.