The watchdog has pushed back the deadline for its final decision until 18 Novmeber to “allow additional time to consider the proposed acquisition”.

The ACCC was initially expected to make its decision on 3 September but pushed back the deadline to 17 September, before then giving itself until 12 November to hand down its final verdict.

It raised concerns in September the merger could lead to an increase in gas prices and lower supply to Australia's east coast gas market if Shell's 50%-owned Arrow Energy, which holds the largest uncommitted gas reserves on the east coast, was to sell its gas to BG's Queensland Curtis liquefied natural gas project.

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