''They're thanking their lucky stars it wasn't up against the house or it could've been a different story,'' he said.
The firefighters got back to the station about 5am.
Fire investigator Craig Bain said the blaze may have been caused by rodents chewing on electrical wiring.
''This is a really bad year for them [rodents]. They're everywhere.''
It is understood the couple had bought the bus just three weeks earlier. They had planned to set off on holiday this weekend.
Later, about 9.50am on Tuesday, firefighters were called out to resolve a courtroom drama when a woman became trapped in a toilet at the Kaikohe District Court.
The incident occurred at courtroom two where toilet facilities have been recently upgraded.
Kaikohe fire chief Bill Hutchinson said it appeared a mechanical failure of the lock caused the woman to be trapped for about 15 minutes.
Firefighters removed the trim around the door then got a screwdriver into the gap to force the lock open.
The rescue only took a couple of minutes, he said.
Also yesterday, about 1.30pm, the Kerikeri Fire Brigade was called to an incident at a bed store in Waipapa when a light fitting exploded and dropped onto a counter.
It was put out before the brigade arrived by a staff member using a fire extinguisher.
It was fortunate the burning fitting hadn't dropped onto nearby mattresses, Wasson said.