Victoria’s auditor-general has found the state government cannot show if, or how, it is preventing the decline of threatened species.

Experts say about a third of Victoria's flora and fauna are facing extinction. 

The Department of Environment, Land, Water and Planning (DELWP) has told the auditor-general that it cannot guarantee the protection of all threatened species with its current funding levels.

But the auditor-general’s report, which has been tabled in state parliament, say the department’s reporting on biodiversity and threatened species protection “lacks accountability and comprehensiveness”.

It found government investment in a 20-year plan to halt biodiversity loss fell $110 million short in its first four years, leaving it with an annual shortfall of $38 million in ongoing funding.

The department said its level of funding is “likely to result in the state's inability to preserve its 10 endangered icon species” and “many more vulnerable species becoming endangered”.

DELWP was found not to have provided “detailed, evidence-based advice to the government about the cost and benefits of protecting and monitoring threatened species to support further investment”.

The department was also found to have underused legal mechanisms at its disposal to protect species, including two under the Flora and Fauna Guarantee Act, which has never been used.

It is a matter of the environment minister’s discretion to use these laws.

Environment Minister Lily D'Ambrosio gave no explanation for why the measures had not been used to date.

The Victorian National Parks Association has described the report as “damning”. The association says the state government is not only failing to reverse the decline of threatened native plants and wildlife, but it is actually “presiding over their demise”.