A panel of government-appointed experts has uncovered "integrity issues" with the Coalition's flagship climate change policy, triggering a warning that some of the emission reductions claimed by Australia may not be genuine.

The findings relate to the Abbott-era Emissions Reduction Fund, established in 2014 to replace Labor's so-called "carbon tax". The Morrison government extended the fund in February with a $2 billion injection of taxpayer funds, and renamed it the Climate Solutions Fund.

An official committee has raised concerns over carbon farming methods under the Emissions Reduction Fund. Credit:Bloomberg

The direct action initiative gives financial incentives, in the form of credits, to projects that reduce carbon emissions or draw them from the atmosphere, such as by revegetating land.

An official panel of experts has identified "integrity issues" with two revegetation methods under the fund. Among the committee's findings are that some projects may have received credits for carbon sequestration that has not yet occurred and may never occur - for example, because the land is not capable of growing forest cover.