ACT Climate Change Minister, Shane Rattenbury, has slammed the Federal Government's national energy policy as "false advertising" and a "Frankenstein's monster" of policies.

The ACT Government today indicated it would not support the National Energy Guarantee (NEG) in its current form, just a week out from a major meeting of the country's energy ministers.

Mr Rattenbury said the NEG was "cobbled together out of bits and pieces" of policy that had not been ruled out by sections of the Coalition party room.

"Unfortunately in its current form, the NEG is largely false advertising, won't achieve what it promises, and in fact it is likely to have a negative impact in all of the areas it claims to improve," he said.

"One of the other ironies is that this policy is designed to deliver certainty and we can see that the low level of ambition that is built into it means there will not be certainty.

"As soon as there is a change of Federal Government in Australia a new target will be put in place."

The NEG requires electricity retailers to supply enough energy to cover peak loads while also meeting emissions reduction targets.

Next Friday at the COAG meeting, Federal Energy Minister Josh Frydenberg will attempt to persuade states and territories to sign up to the NEG.

What the ACT wants from NEG: more frequent reviews to assess emissions reductions against the Paris agreement

more frequent reviews to assess emissions reductions against the Paris agreement 26 per cent reduction target locked in as a permanent floor

26 per cent reduction target locked in as a permanent floor assurance NEG will not be used to support coal-fired power stations

assurance NEG will not be used to support coal-fired power stations confirmation that states and territories can pursue their own targets that exceed the Commonwealth's

confirmation that states and territories can pursue their own targets that exceed the Commonwealth's state and territory renewable energy targets to be additional to national target

But the ACT could become a hurdle, with the Legislative Assembly today passing a motion calling for improvements to the policy to address shortcomings — including a weak emissions reduction target, likely poor economic outcomes, a failure to recognise state and territory renewable energy targets.

The assembly also noted the "likelihood [the NEG] would be used as a Trojan horse for policies to prop-up Australia's coal industry" and called on the ACT Government to only support a policy that would transition the energy market to a sustainable and affordable energy system.

"The current NEG proposal we do not believe will achieve this," Mr Rattenbury said.

But he said he was optimistic states and territories could find a "sensible way" through the negotiations.

"We are working with other jurisdictions to come up with a unified position on what we can put on the table," he said.

"I think it's useful to do that work prior to the actual meeting so the different jurisdictions can come up with working solutions."

We won't let NSW freeload off the ACT: Barr

Chief Minister Andrew Barr said state and territory renewable energy targets must be additional to the national emissions reduction target, to prevent some states piggybacking off other's efforts.

"It assumes all voluntary effort by state and territory governments that have already set more ambitious renewable energy and emission reduction targets will be subsumed into the national effort," he said.

"So in effect the ACT, Victoria and Queensland will be doing all of the heavy lifting on national emissions reductions through our ambitious schemes — leaving states like New South Wales to freeload off our efforts.

"That isn't fair and it isn't good enough."

The ACT has a 100 per cent renewable energy target by 2020.

"We will not let our community's leadership on renewables become an excuse for other parts of Australia doing less," Mr Barr said.

He said if the Commonwealth agreed to a series of changes, it would go "a long way" towards securing the ACT's agreement.

The Canberra Liberals did not vote against the call for improvements, but Opposition Leader Alistair Coe said the minister should get on with his job instead of grandstanding.

"Surely it's the minister's job to advocate for the ACT in this area," he said.

"He should not need to move motions calling upon himself to do what he should have already been doing, and that is seeking a better deal for Canberra's energy consumers."

The ACT Opposition supports the 100 per cent renewable energy target.