Some of the carbon offsets operating under a controversial $2.5 billion fund set up by the Abbott-Turnbull government are at "significant risk" from bushfires, according to a review by the Climate Change Authority.

The audit of the Emissions Reduction Fund, released by the authority on Monday, released by the authority on Monday, found that evidence of systemic problems had yet to emerge, but that there were questions over whether some of the carbon stored under the scheme would have been stored anyway.

The report noted the fund had so far paid out $2.23 billion for 189 million tonnes of emissions reductions, or about $11.80 per tonne. Some 26 million tonnes had already been delivered.

"Overall, this review has found that the ERF is generally performing well," the report said. "It has successfully incentivised new domestic abatement at low cost that will help contribute to Australia meeting its international target commitments."