Early on Monday, an alert neighbour spotted flames at Oamaru’s Martyns Cycles, in what turned out to be a "suspicious fire" at the back of the Thames St business.
Owner and manager Brent Martyn received a call from the Oamaru Volunteer Fire Brigade to say they were dealing with a fire at the back of his family business.
An alleged offender or offenders had apparently deliberately lit a high pile of cardboard boxes and other material stacked at the rear of the premises, he said.
The blaze spread into the eaves and roof of the cycle shop’s workshop and an adjoining storage shed.
It also left the entire main retail area reeking of smoke — forcing the retail part of the business to close for the rest of the week for a deep clean.
Mr Martyn said the fire was quickly put out thanks to Fire and Emergency New Zealand, before he arrived.
"If it had been much longer, I don’t know if this would all be here right now.
"I got here and walked in and I couldn’t see the front door from back there.
"It was just that thick smoke," he said.
The main retail area and stock was affected, and the business was forced to undertake a major clean.
Mr Martyn, his family and staff spent Monday morning cleaning up debris and assessing the damage that had been caused.
The fourth generation in the family cycle business, Mr Martyn said it could have been "a lot worse".
But the cost of the fire could yet be many thousands of dollars.
They had been "very lucky" that neighbourhood watch was alive and well in Oamaru.
Mr Martyn paid tribute to the neighbouring Shortblack Cafe staff member who had raised the alarm.
Passersby on Thames St had also alerted him to the smoke inside the store.
Fire and Emergency New Zealand Waitaki group manager Mike Harrison said two Oamaru Volunteer Fire Brigade crews quelled the blaze.
"The fire was suspicious and the investigation is ongoing.
"It was an excellent response from the Oamaru Fire Brigade.
"Their quick actions and response times definitely contributed to protecting the building and other buildings that were in that area," Mr Harrison said.
Mr Martyn said the Oamaru police had also acted quickly in the aftermath.
That included securing adjoining CCTV security footage from another business’ premises.
As a result, they already knew that the fire had been lit about 10pm on Sunday night, he said.
"It’s been smouldering for a long time before it actually went off into flames.
"I’m wondering if they came here, jumped up here, maybe by mucking around on the roof or something," he said.
He hoped the police would quickly catch the culprits, Mr Martyn said.
It followed two recent suspicious incidents in the area that had been reported.
They included an attempted break in at a neighbouring business, and youths being sighted on rooftops.
Oamaru Detective Sergeant Rory McGeown said the fire was believed to be an "isolated incident".
However, they were following "a positive line of inquiry".
"With the trespassing and the fire, we’re assessing links between these incidents and other youth behaviour in town that we’re aware of.
"We do have a good grasp on this situation," he said.