Job cuts have left the government body responsible for air-traffic control in Australia in crisis, with senior Airservices officials providing damning accounts that the organisation is now "a huge risk to public safety".

Key points: Airservices staff fear it could take 'blood on their hands' before changes are made

Airservices staff fear it could take 'blood on their hands' before changes are made More than 700 jobs have been cut from the organisation to date as part of cost-cutting

More than 700 jobs have been cut from the organisation to date as part of cost-cutting Senator Nick Xenophon is demanding an immediate cease of the retrenchments

"It's only a matter of time before we have a major aviation incident," one Airservices executive has told the ABC.

As a result of a cost-cutting program known as Accelerate, Airservices Australia suffered a net loss of more than 700 staff.

But the organisation has insisted the cuts only affect backroom support staff and not frontline workers such as air-traffic controllers and airport firefighters.

The definition of "frontline" has been hotly disputed among staff, as the cuts include positions such as safety specialists, radiation hazard inspectors, flight simulator training operators and environmental noise managers.

Fears about Airservices' capacity to manage problems in the skies had been debated since executives learned of how extensive cuts would impact their operational areas last July.

But these simmering anxieties reached a new flashpoint when a thunderstorm erupted over Melbourne just after Christmas last year.

As the sudden deluge hit Tullamarine airport, passenger flights were left in holding patterns for over 70 minutes.

One Jetstar flight arriving from the Gold Coast was hit by dangerous turbulence, forcing it into an escape manoeuvre at full thrust to regain control.

Inside the towers, air-traffic controllers juggled the increasingly crowded skies.

Back at Airservices' National Operations Centre in Canberra, staff responsible for communicating between air-traffic control, airlines and airports worked overtime as phones rang off the hook, according to workers with first-hand knowledge of the event.

It was one of the first major tests for the organisation since the job cuts began rolling out.

Leaked emails reveal fears about public safety

When the evening shift on December 29 was nearly over, an explosive email exchange, which has been obtained by the ABC, flared up between senior managers in the National Operations Centre, who described a system at "breaking point" brought on by the "sheer lunacy" of how the cuts have been implemented.

One senior official pleaded to his colleagues: "We barely pulled through with five trained staff and other favourable conditions [in other cities]."

A leaked Airservices email exchange detailing concerns about job cuts. ( ABC News )

Then followed a stark warning for what the job cuts still to come would mean for the travelling public.

"Attempting a night like tonight with only two on shift is sheer lunacy. What happens when there are only two staff?

"Do we need to wait for a mid-air collision or can we deal with this proactively?

"How much blood needs to be on Airservices' hands before we're given appropriate coverage?"

Got a confidential news tip? Email ABC Investigations at investigations@abc.net.au For more sensitive information: Text message using the Signal phone app +61 436 369 072 No system is 100 per cent secure, but the Signal app uses end-to-end encryption and can protect your identity. Please read the terms and conditions.

In the lead up to this event, Airservices insiders had been questioning whether public safety was playing second fiddle to short-term savings; for some managers in the national headquarters, the chaos in Melbourne that night had proven their suspicions.

The ABC has spoken to dozens of current and former Airservices employees throughout its investigation into the troubled government organisation; this is just one of the many damning accounts of how the critical air navigation service provider is "flying blind".

'Only a matter of time' before major incident: whistleblower

Australia's track-record for aviation safety has been very strong by global standards.

But the Accelerate program, which is known colloquially in the organisation as "cutting to the bone", has resulted in an erosion of confidence in its current leadership, according to internal critics.

An executive with oversight over the organisation has told the ABC the risk assessments made in relation to Accelerate have amounted to little more than "a box-ticking exercise".

"There is a culture of cover-up and deceit which means problems are ignored and fingers are pointed," the Airservices executive told the ABC on the condition he was not named.

"The organisation has been ignorant to how certain non-frontline capabilities and staff can have catastrophic frontline impacts."

The whistleblower argued that Airservices chief executive Jason Harfield had forged ahead with the job-shedding program despite internal concerns over aviation safety.

Suggestions Airservices compromising safety 'totally incorrect'

Mr Harfield has declined repeated requests by the ABC for an interview to address these concerns, instead responding with a statement:

"Any suggestion that Airservices is compromising on safety is totally incorrect and refused. There is no risk to the travelling public. "It is important to note that throughout the Accelerate program there has been extensive union and employee consultation. Airservices takes feedback from our staff very seriously. "All 'risk assessments or safety assurances' have been conducted in adherence with … pre-determined timelines."

The whistleblower has also raised doubts about whether a Senate Estimates hearing on October 17 was given the full picture of the impact of the job cuts.

"There was a high level of anxiety within the leadership team and the risk and assurance team about this, but all of the issues and concerns were ignored by the change managers and executive," the Airservices executive said.

"The organisation's risk system was not and still has not been used to assess or manage risk on an ongoing basis in relation to the changes or Accelerate program."

Mr Harfield, in his statement to the ABC, rejected these allegations as "totally incorrect".

Documents obtained by the ABC under Freedom of Information (FOI) legislation show seven change risk assessments were not finalised until October 21, well after the forced redundancies were already in full-swing and four days after Mr Harfield's testimony to Senate Estimates.

The ABC has been told that senior officials were pressured to sign off on required safety work that had been rushed through in the days immediately following Senate Estimates.

Airservices has rejected any suggestion that the assessments were impacted by Senate Estimates.

Senator pushing for investigation into 'shocking' revelations

Sorry, this video has expired Senator Nick Xenophon calls for investigation into Airservices Australia cuts

Senator Nick Xenophon sits on the Senate committee to which Airservices answers.

He is demanding an immediate stop to the organisation's retrenchments until an independent investigation has been conducted.

"When those on the inside say that there's a very real risk to public safety, that we are looking at a catastrophic event unless these matters are dealt with — then that has to be dealt with as a matter of absolute urgency," Senator Xenophon told the ABC.

"These revelations are actually quite shocking because we know that the system's been under pressure, we know that it's been dysfunctional — and now we know for the first time how bad things really are.

"This really is mayday for air-traffic control in this country."

The advocacy group representing Australia's general aviation pilots, the Aircraft Owners and Pilots' Association (AOPA), is backing Senator Xenophon's call for a full and independent investigation.

It argues the flying public need to know how much safety work was done and when.

"Certainly Mr Harfield was not ambiguous in his statements to Senate Estimates that the safety analysis documents were in existence and that the Accelerate program was being undertaken in accordance with those," AOPA chief executive officer Ben Morgan said.

"So I believe there really does need to be a detailed investigation into those documents to determine the legitimacy of them."