There's confusion over how an $800 million lifeline for a renewable energy agency will be funded after the government claimed there will be no new spending.
It's prompted Labor to question the coalition's accounting methods, saying they don't stack up.
In a deal struck on the government's omnibus savings bill on Tuesday, Labor negotiated for the Australian Renewable Energy Agency to keep $800 million for grants over the next five years.
The government had planned to cut $1 billion - all of the agency's new grant funding.
The coalition says the funding will be stripped from another renewable body - the newly created $1 billion Clean Energy Innovation Fund.
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Finance Minister Mathias Cormann insisted the move had "no effect on overall government debt" because it would be "reducing the amount of capital available for concessional loans" to the same degree.
Environment Minister Josh Frydenberg later confirmed the $800 million would come from the Clean Energy Innovation Fund, which provides loans - not grants - for emerging technologies.
Labor says in accounting terms offsetting a grant spend with a loan allocation - which doesn't sit on the government's books - doesn't work.
"You can't just take equity from a government corporation and spend it in an appropriation sense," a Labor spokesman told AAP.
"This is creating confusion for the industry."
The Clean Energy Innovation Fund was created by the Turnbull government earlier this year and is co-administered by ARENA and the nation's renewable-energy bank - the $10 billion Clean Energy Finance Corporation.
The money came from the CEFC - so the corporation was left with $9 billion to work with for the rest of its financing.
Senator Cormann insists the overall $10 billion CEFC capital won't change.
AAP understands the CEFC has not been consulted about the changes.
If the government could reprioritise the CEIF loans to ARENA grants, the $800 million would reduce net financing in renewable energy.
The Greens believe Labor has been "seemingly played for fools" on the deal which still cuts $500 million from the agency.
"It seems the finance minister thinks the government still gets to rip over a billion dollars from clean energy," Greens MP Adam Bandt said.
Labor also argues the government is trying to offset the $800 million spend twice, saying the funding was already offset by other savings offered in the omnibus deal compromise.
The renewables sector has suffered a tumultuous couple of years after a lengthy political stalemate over the legislated renewable energy target injected uncertainty and slashed investment.
