"There was very little communication to passengers. No one knew what was going on," she said. "The pilot was very vague and called it 'an indication' that we had to return to Sydney"
Passengers stayed on the plane as firefighters investigated the incident.
"They looked to be measuring the air," Bale said. "I was pretty nervous and just wanted to get off the plane."
The origin of the odour has not yet been determined.
The Jetstar spokesman said the airline was working to re-organise flights for those affected and had a spare jet in Sydney.
Major delays were not expected, he said.