Union officials fear the loss of up to 60 positions by June 30 could be followed by hundreds of job cuts with reports staff are being "kept in the dark".

The government-owned corporation has not confirmed the scale of job losses but has warned there is "no magic number". Close to half of the middle management cohort are expected to depart on June 30.

Chief executive Jason Harfield has written to staff insisting he would not know the full impact of job losses until a wholesale review of operations progressed.

"Be assured that we are working as quickly as possible to resolve uncertainty in a fair, responsible and considerate way," he said.

The restructure has been prompted by a dramatic fall in revenue and increasing costs and hopes – with the assistance of PricewaterhouseCoopers – to slash $100 million from its cost base in coming years.

Profitability has plummeted by 90 per cent from $45.5 million in 2013 to $4.5 million in 2015. The group is expected to post its first financial loss of $13.6 million this year

Internal briefings, obtained by Fairfax Media, reveal the group's corporate section is likely to be hardest hit with job losses to progress "as rapidly as possible".

"Our corporate centre is now too large to be the efficient and agile business that we'll need to be in the future," the briefing said.

"As our corporate centre has grown, costs have increased and we've added layers of administration beyond what we need to support the frontlines that serve our customers.

The briefing sent to the agency's 4400 staff said the scale of job losses would be determined by November at the latest.

"We need to make sure we are doing it right. It is important to note that there is no magic number," the briefing said.

"This is not just a cost-cutting exercise as we can't continue to operate this way and any inefficiencies need to be corrected."

Management has promised to supply transparent updates during "a difficult time of uncertainty for many staff". A spokesman said consultations with staff were ongoing and officials met unions as recently as Wednesday.

But Professional Australia campaign director Matt Harris, whose union represents public servants at Airservices Australia, said staff were being "kept in the dark" about the scale of cuts.

"Airservices is keeping the number of jobs in plans to cut a secret, we just don't know the full extent of their plans," he said.

"It's putting a huge strain on employees. Without any clarity around the numbers, there is a real sense that no one is immune from these cuts."

Some union officials have also raised concerns about the timing of the restructure in the midst of caretaker period and an election campaign.

"It would appear that Airservices has not briefed either the government or opposition on its proposed cuts," Mr Harris said.

"This is worrying, especially when you consider Airservices is wholly owned by the government and the impact these cuts could have on service delivery."

A new leadership team will be announced on July 1 and tasked with deciding how many staff are required for each section of the workforce.

The restructure comes before the implementation of the $1.5 billion OneSKY program, which will combine civilian and military navigation systems by 2021.

Airservices Australia employs more than 4400 staff and manages 11 per cent of the world's airspace. It has 29 towers and 1000 air traffic controllers around the country. Last year it managed the movement of 4.5 million flights carrying 90 million passengers.