The report by consultancy EnergyQuest on behalf of Australian Energy Producers, said "blackouts loom for millions of homes and businesses in southeastern Australia in as little as two years" if the Greens' policy was enacted.
The Greens want an immediate ban on the build of new coal, oil and gas infrastructure in what the party says will transition the economy to zero carbon energy while maintaining a safe climate.
But the Greens platform on gas would lead to manufacturers closing, and long-term Queensland export contracts being cancelled, according to the report.
"A halt to investment in gas supply would devastate the economy. Gas for east coast electricity could be interrupted within two years and would run out by 2029," it said.
Australian Energy Producers chief executive Samantha McCulloch said investment in new gas supply was urgently needed to meet domestic demand.
"The Future Gas Strategy is clear that the Australian economy will need gas to 2050 and beyond," Ms McCulloch said in a statement.
The industry-backed report comes after the federal government this month said emissions from coal and gas could grow by 1.7 billion tonnes by 2050 if their use was extended another 15 years.
Under the government's strategy for gas, the fossil fuel will be in the energy mix beyond 2050, when Australia is due to meet a legislated target of net zero greenhouse gas emissions.
The Greens say by investing in wind power, solar and energy storage, and rewiring Australia's electricity grid, the economy can be re-powered without new gas investment.
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