NSW has accused Victoria of jeopardising the interests of electricity users by making a last-minute call to delay talks on the Turnbull government's National Energy Guarantee until after it is legislated in the Federal Parliament.

Don Harwin, NSW energy minister, rejected a demand on Thursday by his Victorian counterpart Lily D'Ambrosio that the federal government not seek approval from COAG until the policy was law. The ACT said it was open to supporting Victoria.

Lily D'Ambrosio, Victoria's Energy, Environment and Climate Change minister, says the whole National Energy Guarantee process has been mishandled. Credit:Darrian Traynor

Victoria's proposal has been criticised as "shifting the goalposts" a day before state and territory ministers are due to sit down in talks with Josh Frydenberg, the federal environment and energy minister, in Sydney. Mr Frydenberg has been pressing the states to agree on the scheme, which is designed to reduce carbon emissions from the electricity sector while also boosting reliability of the grid and lowering power prices.

"The Victorian government is putting their own election campaign before the interests of Victorian electricity consumers," Mr Harwin told Fairfax Media. The Andrews Labor government was "more interested in protecting the seats that are vulnerable to the Greens" than backing a plan that would lower power prices, he said.