Avoid getting ''burned'' and use a certified gas fitter, Gas & Water director Sean Reynolds, of Dunedin, says.
Gas fitters illegally installing gas appliances in Otago should be ''brought to task'', he said.
Consumers should look on the Plumbers, Gasfitters and Drainlayers Board website to see if the gas fitters they intended to use were certified.
''Look them up or you might get burned.''
Board chief executive Max Pedersen said it took a gas fitter six years of training, work, exams to become certified because the public health stakes were high and uncertified work could have ''horrible'' consequences.
''Gas fitting not done properly can result in carbon monoxide poisoning, explosions and fire.''
Last year, the work of an unlicensed gas fitter left a house filling with gas. It blew up when the resident switched on a light, he said.
The board instigated prosecutions in the District Court against those working illegally in the industry.
In the past financial year, the board was involved in prosecutions against 17 defendants for 22 alleged breaches.
Consumers seeking a gas fitter should request proof of board registration or search for them on the board's website.
If an illegal installation malfunctioned, insurance companies would not pay out, he said.
The board had no taxpayer contribution and was a not-for-profit body whose operational revenue was collected from fees from registered and licensed tradespeople, Mr Pedersen said.
Dunedin City Council building services manager Neil McLeod said gas fitters were self-certifying but council consent for installations was required.
''Energy work - electricity and gas - is exempt for the need for building consent. They are a self-certifying, closed trade.''
