Australia's most threatened species could slip into extinction without anyone noticing, with jobs being slashed at the federal Department of Environment, the ABC can reveal.

Key points: Environment Department to lose 60 positions from biodiversity division

Environment Department to lose 60 positions from biodiversity division Job losses will affect threatened species monitoring program

Job losses will affect threatened species monitoring program Some species could become extinct and no-one will notice.

The department is losing up to a third of its staff who work to stop Australia's world-leading and accelerating extinction rate, documents obtained by the ABC show.

Those cuts come as the first national review of threatened species monitoring found about one third of the 548 species were not being tracked at all.

The researchers found the poor tracking was driven by factors likely to be exacerbated by the job cuts.

"Cuts at the federal level to that end of the process is just kneecapping really," Dr Sarah Legge from the government-funded Threatened Species Hub said.

Professor David Lindenmayer, an ecologist from the Australian National University, described the cuts as "an absolute calamity for the Australian environment and for the conservation of Australia's ecosystems and threatened species".

"Without reasonable numbers of staff it becomes very difficult to deliver good programs and it becomes very difficult to do things such as stop species from going extinct," he said.

Division to lose 25pc of budget, one third of staff

Documents distributed to staff in the Department of the Environment and Energy show "approximately 60" full-time equivalent staff will be lost from the biodiversity and conservation division in the next financial year.

A spokesman for the department told the ABC the division currently had just more than 200 full-time equivalent staff, meaning the cuts could wipe out about a third of that.

The documents said the job losses were a result of a 25 per cent cut to the biodiversity and conservation division's budget "anticipated" in the coming financial year.

When asked to clarify what budget measures were the source of that cut, the department spokesman said: "The Department of the Environment and Energy will publish its budget position next week as part of the 2018-19 budget."

He said the job losses were a result of both cuts to programs, as well as "other budget pressures across the portfolio".

The biodiversity and conservation division coordinates the listings of threatened species and their recovery plans, devises Australia's national biodiversity strategy, and coordinates action around the country against invasive species and other biosecurity threats.

The documents show the department expects to redeploy staff into other positions, but the union, scientists and conservationists said the cuts will be bad news for Australia's threatened species and biosecurity.

"The biodiversity and conservation division are really critical and this is a heavy cut, and it difficult to see how they're going to absorb these cuts moving forward," said Beth Vincent-Pietsch, deputy secretary of the Community and Public Sector Union (CPSU).

"The crucial works they do both in terms of good policy, good administration, good regulation — how can that continue without the staff there to do it? It doesn't make sense," she said.

The cuts follow years of slashed spending on the environment, according to Matt Rose, an economist at the Australian Conservation Foundation (ACF).

He recently examined government spending over time and found it had been cut by about 60 per cent in the forward estimates since the Coalition won government.

'No idea' of threatened species' status

Researchers at the Threatened Species Recovery Hub in the Federal Government's National Environmental Science Program found about a third of Australia's threatened species and 70 per cent of its threatened ecological communities were not being monitored at all.

"It means we have no idea what the population status and the trends are," Dr Legge said.

"It's certainly possible that we could have listed nationally threatened species that are in decline — even rapid declines — and we wouldn't know about it until it was too late."

The review concluded the species with the worst monitoring were limited by poor logistics and resourcing.

Those species that had recovery plans, for example, tended to be better monitored and had better outcomes.

Dr Legge said that made the cuts to the biodiversity and conservation division particularly worrying, since it could delay threatened species being listed and having recovery plans implemented.

Professor Lindenmayer said it could result in more extinctions.

"Without reasonable numbers of staff it becomes very difficult to deliver good programs. And it becomes very difficult to do things such as stop species from going extinct," he said.

Mr Rose agreed: "So if you get rid of staff this process takes longer. Now, threatened species and endangered species can't wait three to four years to go through a government process and be listed."

"They don't have that type of time."

Cuts could make it harder to fight off fire ant 'threat'

The biodiversity and conservation division is also responsible for coordinating responses to biosecurity threats and invasive species. Andrew Cox, CEO of the Invasive Species Council, was shocked by the size of the cuts and said they would hamper the country's ability to fight threats to the environment like fire ants invasions and destructive weed species.

"Without the staff there won't be any plans in place to act on these major threats," Mr Cox said.

He said current staffing and funding levels were already too low.

"We haven't even identified what the main things are that we should be worried about and decisions have been made by public servants with expertise in agriculture rather than the environment," Mr Cox said.

In a statement, a Department of Environment and Energy spokesman said cuts to the biodiversity and conservation division were "the result of several factors including ending programs such as Green Army and Biodiversity Fund and responding to other budget pressures across the portfolio".

A spokesman for Environment and Energy Minister Josh Frydenberg said the Government would not comment on budget speculation, and the department's budget position would be made clear next week.