Origin Energy, the Australian group that repelled an A$13.8bn takeover bid from the UK’s BG Group before agreeing a lucrative joint venture with US oil group ConocoPhillips, has forecast a bumper rise in current year earnings of as much as 40 per cent.

The energy retailer that is developing its Queensland-based coal bed methane gas assets said the uplift was based on “current market conditions for oil prices, exchange rates and interest rates” together with expected timing of payments from ConocoPhillips proposed A$9.6bn investment in their joint venture.