The plan to impose a 10-year ban on new gas-fired or coal-fired power stations will probably be abandoned by Labour and would certainly be ditched by a National government, a leading energy and resources lawyer says.

The oil and gas industry has strongly opposed a ban because it would discourage further exploration for gas and mean big rises in wholesale electricity prices.

"Absolutely it would go [under a National government]," Bryan Gunderson, a Kensington Swan partner, said. "Assuming a Labour government [after the election], you might see it go anyway."

The planned Emissions Trading Scheme, which includes the ban, was not expected to be passed in its present form before the election because time was running out and Labour did not have enough support from minor parties to pass the legislation.