Staff at one of Australia's busiest airports have been setting up camp and sleeping at work, which they say is because they cannot afford to go home between shifts.

Key points: Secret video shows makeshift beds where airport staff are sleeping under terminals

Secret video shows makeshift beds where airport staff are sleeping under terminals Workers say split shifts mean it is not worth going home

Workers say split shifts mean it is not worth going home Employers defend safety record and reject accusations of poor treatment

Secret footage obtained exclusively by 7.30 revealed bed rolls and dirty sheets next to the baggage carousel in the staff-only area of Sydney Airport's international terminal.

Napping between shifts is a result of the "Americanisation" of the Australian workforce, according to the Transport Workers Union (TWU).

Split shifts that start early and finish late and limited guaranteed hours mean it is not worth workers' while — financially or timewise — to return home when they are rostered off, according to the union.

Workers have voiced concerns that fatigue levels are putting safety at risk.

Do you know more about this story? Email 7.30@abc.net.au

'We end up sleeping under the terminal'

Driver George Orsaris believes he will lose his job for speaking with 7.30, but wants to expose working conditions at his employer, Aerocare.

"We get pushed to our limits. Our pay doesn't match it. We don't get rest breaks and we get given a four-hour shift in the morning and then we have a four-or-five-hour break and get a four-hour shift in the afternoon," he said.

"It is barely enough time to sleep by the time you get home, get up and have to go to work again. So we end up sleeping under the terminal where all the baggage goes between."

George Orsaris said he and other workers sometimes slept under the terminal between shifts. ( ABC News )

Most of Aerocare's workers are permanent, part-time with a guaranteed minimum salary of about $16,000 per year under a collective agreement approved by Fair Work in 2012.

TWU national secretary Tony Sheldon said the company sought to "game the system" in the pursuit of profits by keeping workers "hungry" for shifts, despite the long breaks in between.

"Quite clearly, these agreements are deficient, they are unethical," he said.

"When you are getting paid below the poverty line, when you can't raise a family on these incomes and the company clearly knows that having them part-time is starving the workforce into submission.

Workers raise safety concerns

Aerocare workers have told 7.30 they were concerned fatigue had contributed to two safety incidents.

In November 2014 in Brisbane, a Tiger Air cargo door was left open but discovered before take-off. Mr Orsaris said lives could have been at risk.

"If it was missed and the plane was to take off down the runway, I'd hate to think what would happen," Mr Orsaris said.

Aerocare said the safety of crew, passengers and ground staff was never at risk.

The company's chief executive, Glenn Rutherford, said in a statement he was concerned about "any allegations of system deficiency" and would further investigate any claims.

"We want to ensure it is on record that in 22 years, and despite handling over a million flights, Aerocare has never been penalised for a safety issue," he said.

A makeshift bed in a staff-only area near the baggage carousel at Sydney Airport's international airport. ( ABC News )

Aerocare rejects accusations of 'poor treatment'

Aerocare said it provided full-time positions wherever possible, but that its rostering was to a large extent determined by the airlines' flight schedules.

It said 97 per cent of employees voted in favour of the current enterprise bargaining agreement.

"Aerocare strongly refutes any allegations or assertions … inferring poor treatment or under-payment of its employees," a spokesman said.

The company said it provided better job security and working conditions than many of its competitors and had committed to increasing pay rates by 5 per cent across the board.

"Aerocare has invested millions of dollars to improve the quality of its rostering so as to maximise the duration of shifts, with the goal of securing more contracts which would enable Aerocare to offer employees longer shifts and further viable full-time positions," the spokesman said.

Aerocare's most recent financial statement to the corporate regulator showed net profits were up more than 20 per cent to $13.5 million in the 2016 financial year.

Mr Sheldon said that other companies were now replicating the wages and conditions of workers at Aerocare, which is owned by private equity firm Archer Capital.

"We've seen the Americanisation of the Australian workforce in the aviation industry and yet we've seen executive bonuses increase, we've seen airport profits in the billions and this future is really something that beholds for everybody across the Australian workforce," he said.

Read Aerocare's response in full:

Loading...