A two-well gas appraisal programme is planned to start later this year on the large Lockyer Deep-1 gas discovery in Western Australia's red-hot Perth basin.

The two wells - North Erregulla-1 and Lockyer-2 - will be drilled back-to-back starting in the fourth quarter, subject to rig availability, land access and regulatory approval, said joint venture partner Norwest Energy.

The Lockyer-3 and Lockyer-4 wells are also in the planning stage, with final locations and timing to be confirmed based on the results of the first two wells.