According to media reports, the Dash 8 Q300 jet with 50 passengers was evacuated and the pilot and co-pilot were admitted to a hospital for assessment.
ACT Fire & Rescue and ACT Ambulance Service Intensive Care paramedics were called to the scene just after 12.30pm (local time) when the Sydney to Wagga flight was diverted.
The Flight QF2225 left Sydney at 11.30 am and was due to be in Wagga Wagga about 12.30 pm.
A Qantas spokeswoman said the cause of the smoke was being investigated.
"All passengers disembarked at Canberra airport via the stairs," she said, adding, "No passengers required medical attention."
The passengers have since continued to Wagga Wagga after being transferred to another aircraft.
The spokeswoman added the crew had been cleared of any harm from the incident and discharged from the hospital.
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