Zek Campey is holding on to hope that his father's "beautiful" classic Ford Mustang, stolen on his watch of his dad's Ashburton house, will be returned undamaged.

The 27-year-old said the 1965 American muscle car was taken on Monday afternoon when the house was broken into. His father is overseas.

He posted on Facebook offering an unspecified reward for help in finding his father's prized possession and has been overwhelmed by the response.

By late morning today, more than 800 comments had been placed and the post had been shared more than 7000 times, including in Australia, which one commenter feared would be the distinctive car's destination.

Sightings of it have been reported too, between Ashburton and Christchurch.

Campey said he and his partner went to take the dog for a walk on Monday and noticed things were out of place.

The gate was open, doors were unlocked and a window had been broken.

"I thought, yep, we've been robbed," Campey told Newstalk ZB.

"They've moved a lot of stuff around, drawers have been opened and eventually found the keys to the garage and taken off with the Mustang.

"I've had a lot of people message me saying they saw it going northbound towards Christchurch around the airport and Hornby around 4.30 [on Monday afternoon].

"It's awesome. I can't say thank-you enough to everybody that has put forward their support."

He said he was hopeful - but realistic - about the chances of the car being found.

"I would hate to see it burnt out or parted out [broken up for parts]. That's not what anybody wants to see for a beautiful car like that."

Campey had phoned his father to explain the loss.

"He just took a few moments to clear his head. He took the phone away and I think he said a few swear words. He came back to it and he was pretty calm about it."

The police said they had received a report on Monday evening about the car theft. The Ashburton property was visited, forensic and area inquiries were made, and the investigation was ongoing.