Crews managed to save the house with no damage, but two small outbuildings or sheds were completely destroyed.
A fire investigator was not required, Walklin said.
Conditions were sweltering yesterday in the area, with heat alerts issued for some parts of the South Island by MetService.
Te Whatu Ora, the health ministry, also warned Cantabrians that “scorching temperatures” were expected to hit the region.
Timaru reached 26C, according to MetService, while Niwa said North Canterbury had the highest temperature of the season so far, reaching 33.7C.
Similar temperatures can be expected today, with at least 30C expected for Christchurch, according to MetService.
Fires on Māngere Mountain, One Tree Hill Meanwhile in Auckland, firefighters were called to two fires on volcanic cones yesterday evening.
A large scrub blaze on Māngere Mountain was reported at 4.30pm and extinguished by 8pm.
That fire reached 60m x 50m at its height, with five fire trucks, one command unit and two support vehicles attending. Crews remained on scene until 8pm dampening down hotspots.
It had been deemed suspicious and a fire investigator had attended, Walklin said. The investigator would return today.
Police said they had received reports of three males deliberately lighting fires on the mountain , and duly arrested three males within minutes of arriving at the scene - but then released the trio without charge.
“[Inquiries] are ongoing to locate the person or persons responsible for lighting the fires,” police said.
Still of video captured by James Solomon of a small grass fire at One Tree Hill on evening of December 21. Walklin said a grass fire was also reported at the Domain at One Tree Hill in Epsom just before 9pm.
That fire reached 5m x 10m and three fire trucks attended, extinguishing it by 9.42pm.
One bystander said he had been told by police that fire was started by picnickers with fireworks. Fenz was unable to confirm that report.
The Herald has requested comment from police.
The highest temperature in Auckland yesterday was a humid 26C, with MetService predicting similar temperatures every day until Christmas.
