An arsonist gutted a Hamilton house early yesterday, the latest in a spate of property fires to hit the Waikato during the last six weeks.

The River Rd house was unoccupied when an arsonist struck sometime after midnight, however the Fire Service was not alerted until 12.30am, when neighbours spotted flames coming from the house.

It is understood the Auckland owners of the property were unaware of the fire until rental agents inspected the house yesterday.

Waikato fire risk management officer Kevin Holmes said the investigation was now with police so he could not comment on how the fire started. But he did confirmed it was arson.

But the noise was enough to wake residents, including some from across the river at Pukete, including Gavin Davis.

Mr Davis said he noticed the sound of a "series of quite loud bangs, sounding like fireworks".

The blaze blanketed the northeastern side of the town in smoke, he said.

Later, a fire broke out in the ceiling of a house on Lyon St, Kihikihi. No-one was home when the fire started about 1.30pm.

Station Officer Mike Kimber said the fire was caused by an electrical fault in the ceiling and spread rapidly, and destroyed all of the roof's lining. "The roof is intact but half the roof space is badly damaged."

The fires were two of more than 20 in the greater Waikato region since the winter period began in June, Mr Holmes said.

A Riverlea Rd house fire, which began in a shed before spreading to the house, was originally thought suspicious, but further investigations revealed it was caused by faulty wiring in the shed's internal wall.

About 10 fires had been caused by heaters and chimney fires.

A was also the subject of a product recall notice by the Fire Service's research and investigation unit.

The Kent oil-filled column heater had oil burst out of its columns. The woman told the Fire Service she was alerted by a bang and a pungent smell.

Nine of the heaters have faulted. Some oil-column heaters could be dangerous as the columns swell and burst, spraying out hot oil, Mr Holmes said.

Meanwhile, Matamata's Mark McCarthy, 77, died after falling asleep with a portable heater too close to a miniature table. It caught fire, and he was unable to escape in time.

However, some of the fires could have been prevented, including a Heaphy Tce fire which was caused by an overloaded power point. However, the damage was not serious.

belinda.feek@waikatotimes.co.nz

- © Fairfax NZ News