A third attempt to plug a well that has been leaking oil for more than eight weeks into the Timor Sea off the north coast of Western Australia has failed.
The leak at West Atlas rig began on 21 August, spreading oil across thousands of square kilometres of ocean.
Owners PTTEP Australasia tried unsuccessfully on Saturday to intercept the leak more than two kilometres below the sea bed, the ABC reports.
The company will now assess when the next attempt can be made.
PTTEP Australasia has defended its efforts, saying it has employed members of the leading international company in oil and gas well control.
Australia's Environment Minister, Peter Garrett, announced this week that a deal has been struck with PTTEP for it to pay for environmental monitoring in the Timor Sea for at least two years.