Qantas says there was never any risk to passengers during a flight where an Airbus was overloaded by almost a tonne.

The air safety watchdog says the incident was not reported properly by staff and the airline also failed to carry out proper safety checks after the incident.

The Qantas flight left Sydney for Hong Kong in March 2009.

The Australian Transport Safety Bureau (ATSB) has issued a report saying the plane's load controller gave the wrong information about the amount of freight the plane was carrying.

The incorrect data led to the plane taking off almost one tonne overweight.

The report says the off-loading team in Hong Kong noticed the overload but did not file a report, which meant the plane made another 10 flights before it was checked for faults.

The safety bureau says when it checked with Qantas, it discovered the airline had not conducted quality reviews at the Sydney freight centre for 22 months before the Hong Kong incident.

Qantas says while there was never any risk to passenger safety, it has since made changes to freight checks and incident reporting.