It could have leaked and sparked the fire, the Fire Service said, but there had also been cars inside the building at the time which also could have been a potential cause of the blaze.
Today, the city council's resource consents and building policy manager Steve McCarthy said the gas cylinder possibility had been ruled out.
"There was a suggestion that it might've been part of a cooler cabinet. We've asked our health people for any recollection or record but there's nothing on the file, and there's nothing to suggest a 9kg bottle of LPG gas on that site," he said.
The council had been asked by the commission to trawl council Hazardous Substances Office records to see if there was any evidence of gas bottles being stored inside the Madras St office.
A rescue worker and trained structural engineer, who arrived at the disaster site 30 hours after the collapse, earlier told the commission that he believed crushed cars may have sparked the blaze.
Urban Search and Rescue (USAR) support engineer Graham Frost believes the fire may have started in cars in the ground floor car park.
He saw six cars being removed from the building during the recovery stage in the immediate disaster's aftermath were all burnt out.
Mr McCarthy also confirmed today that the CTV building was not recorded at the council as being potentially earthquake prone because it was built after 1976.
The hearing continues.