The man, who said he was a farmer but declined to give his name, went to the Pak'n Save fuel facility in Invercargill about 2pm.
He filled up a plastic fuel container without incident and said he had just begun to fill the small drum when flames erupted from the top.
''I got a bit of a fright, that's for sure. I'd done the same thing many times before and that had never happened.''
Pak'n Save staff member indicated he should abandon his vehicle by the pump but he decided to drive it out from under the fuel facility canopy.
''I didn't want to see the whole place go up.''
An on site fire extinguisher was used to put out the fire, which left a large hole in the plastic deck tray of the ute and a scorch mark on the rear flap.
Invercargill Fire Service firefighters attended.
Station officer Dean Chalmers said it appeared the fire had been caused by static electricity - where a small electrical spark ignites flammable material.
Refuelling fires had been started by static electricity from cellphones, he said, although the farmer was not using a cellphone.
''Sometimes static discharges just happen, but they are not a common event.''
