The airline confirmed yesterday that flight QF2 had been grounded due to a ''technical issue''.

It is expected to arrive in Sydney at 7.50pm tonight. The Boeing 747-400 was originally due to touch down at 5.30am.

The rudder problem is the latest in a string of mishaps to beset Qantas's fleet since an explosion ripped a hole in the fuselage of a Qantas jet en route from Hong Kong to Melbourne, forcing an emergency landing at Manila on July 25.

On Friday, the airline confirmed that a small access panel had fallen off a jumbo jet as it flew to Singapore from Melbourne.

The problem was discovered during routine checks after the plane arrived at Singapore's Changi Airport.

On Wednesday, a Qantas Boeing 767 had a hydraulic failure which affected the plane's steering as it landed at Sydney airport.

The plane left a trail of hydraulic fluid as it touched down on its way from Melbourne, forcing the closure of the runway for more than 40 minutes while the spill was mopped up.

On August 2, a Qantas Boeing 767 flight turned back for an emergency landing at Sydney airport after a hydraulic fluid leak was discovered.

And a domestic flight was forced to return to Adelaide airport after a wheel bay door failed to close on July 29. AAP