Its upstream operations, driven by Bass Strait, the Cooper Basin and Western Australia, balanced that negativity and lifted $14 million from last year's performance to post a $722 million profit.

ExxonMobil said the refining business' result reflected the 'highly competitive' and 'very difficult' environment that faced the refining and marketing sectors.

The giant recently announced it would be mothballing its Port Stanvac refinery in South Australia due to unsustainable losses.