The ACT government says the federal government's National Energy Guarantee will lock in "poor outcomes" for the climate, renewable energy and electricity consumers.
It was hoped energy ministers meeting in Melbourne on Friday to discuss the guarantee would be ready to sign off on it, but the territory says they've got serious concerns about its current form.
Instead Climate Change Minister Shane Rattenbury says they'll use the meeting to argue for improvements.
The Energy Security Board released a highly technical 54-page document to federal and state governments last week, followed up by a supplementary 11-page document from the federal government late on Friday night.
"While the technical design of the NEG mechanisms prepared by the ESB have an improved approach to account for emissions, there are serious deficiencies in the policy parameters proposed by the Commonwealth on Friday," Mr Rattenbury said.
His major concern is the "weak" 26 per cent emissions reduction target for the electricity sector, as well as failing to recognise work done by individual states to reduce their own emissions and stimulate renewable energy investment.
The prospect of retailers being allowed to use carbon offsets to comply with emissions reduction obligations is also a concern, he said.
At a federal level the Greens have also expressed worries about the 26 per cent emissions reduction target.
It's at the lower end of Australia's Paris agreement commitments to reduce emissions by 26-28 per cent on 2005 levels by 2030.
Legislating the "measly" target could leave Australia without a mechanism to ratchet up that commitment, as was intended by the agreement, Mr Bandt said.
"By dropping the ball on energy, the government has left agriculture and transport with ridiculously large tasks, like taking every cow out of every farm or taking every car off every road, just to meet our paltry Paris commitments," he said.
He's expressed concerns over suggestions federal Labor might support the NEG and seek to increase emissions reduction targets to 45 per cent if they win the next election.
Mr Bandt said if Labor was not elected they'd have helped lock in a scheme that's worse than doing nothing.