MELBOURNE, Nov 10 (Reuters) - A plan by the Australian government to cap gas prices has not stopped private equity investors from lobbing a huge bid for a major Australian gas producer, defying industry warnings that market intervention would stall investment in new supply.

The fear of deterring foreign investment has complicated considerations over what steps to take to rein in energy prices, several government ministers have said over the past two weeks as they aim for a decision before Christmas.

Brookfield Asset Management and EIG-backed MidOcean Energy's A$18.4 billion ($11.8 billion) buyout offer for Origin Energy , announced on Thursday, eased that concern.

The bid includes Origin's stake in Australia Pacific LNG (APLNG) - a major gas producer targeted by the government to help drive down prices.

"This absolutely calls out the lie that governments working in the interests of Australians in an energy crisis will scare off foreign investment," said Tim Buckley, director of Climate Energy Finance, a think tank focused on decarbonisation.

The Brookfield consortium needs clearance from the Australian Competition and Consumer Commission and Australia's Foreign Investment Review Board, which sends its decision to Treasurer Jim Chalmers for final approval.

Credit Suisse analyst Saul Kavonic said Chalmers could use the approval process to apply pressure over prices.

"The government could use its approvals leverage to try and extract concessions on domestic gas supply and pricing," he said.

Spokespeople for Chalmers and Energy Minister Chris Bowen declined to comment on the approvals process.

A spokesperson for Resources Minister Madeleine King did not respond directly to questions about how the bid might affect the government's thinking on price caps, but said: "The Australian Government welcomes investment in the resources sector."

The consortium said it was looking past the looming price controls.

"Brookfield and EIG/MidOcean are both committed to investing in high-quality assets for the long term and working co-operatively with Governments and market regulators as the energy transition evolves," a spokesperson for the consortium said.

"All market participants are vitally concerned to ensure the plentiful supply of affordable and reliable energy for all consumers and we will play a constructive and supportive role in the Australian market.”

Canberra's push to cap prices came after the Labor government released its budget on Oct. 25 which forecast household gas and power prices would rise by 20% to 30% over each of the next two years, partly due to Russia's invasion of Ukraine.

Australia's no.2 independent gas producer Santos Ltd , which runs the Gladstone LNG (GLNG) project next door to APLNG, warned two weeks ago that market intervention would damage Australia's reputation and inflate prices.

"This increasing regulatory burden and threat of intervention will take Australia rapidly down the Argentinian road, doing nothing to increase supply but plenty to scare off investors and drive prices up as gas supply becomes ever more scarce," he said in an emailed statement.

Gas price caps could be attached to an agreement the government has already secured with APLNG, Santos-led GLNG, and Shell-led QCLNG to offer any uncontracted gas to the domestic market before it is offered to overseas buyers, said Tony Wood, energy programme director at the Grattan Institute, another think tank.

Boosting the government's clean-energy agenda, Brookfield has said it wants to invest a further A$20 billion in Origin to build renewable power and capacity to back up intermittent wind and solar power. (Reporting by Sonali Paul; Editing by Stephen Coates)