The incident unfolded about 11.30am when Christian Westergaard, driving his father's car, was on his way to pick up his mother to take her to an appointment at the hospital with other family members.
After he pulled into Weston's self-service petrol station in Main St for fuel, entered his eftpos card details, lifted the nozzle from the petrol bowser and was about to fill up, he noticed smoke and flames pouring out from under the Toyota sedan's bonnet.
A quick-thinking Mr Westergaard hurriedly switched off the station's main fuel-line cutoff switch, before he released the car's hand brake and pushed it about 20m away from the small forecourt.
He then ran to nearby business Ludemann Motors where he called emergency services.
Weston Volunteer Fire Brigade firefighters, wearing full breathing apparatus, took about 15 minutes to extinguish the blaze.
Mr Westergaard was philosophical about the incident and said it "could have happened to anyone".
The vehicle was insured.
Mr Westergaard said it was unlikely that the family's trip to Dunedin would proceed.
