Mr Herron's case is highlighted in a Transport Workers Union submission to the Productivity Commission's review of workplace relations. The Transport Workers Union submission says that traditional directly employed full-time airline workers are being made redundant and replaced with part-time workers. Emerging contracting companies are increasingly employing people on a part-time basis. "The 38 hour week is disappearing to be replaced more commonly with a 20 hour guarantee," the submission says. "New companies guarantee as little as 15 hours per week, some as many as 25 hours." The submission says contractors including QGS and Menzies are offering guarantees of 20 hours work for well below the national minimum wage of $640.90 per week. And it was too difficult for part-time workers to supplement their income because their working hours were not set and constantly changed.

Workers in precarious jobs were also less likely to be unionised. The ACTU is on Tuesday calling for the productivity commission to support the creation of a portable entitlements scheme for non-permanent employees. It also wants casual workers to be given the legal right to become permanent employees ACTU President Ged Kearney said one in five Australian workers worked on a casual basis and "deserve the respect and recognition of decent, secure work and entitlements". "The government wants to swing the pendulum in favour of employers and take away rights at work," Ms Kearney said.

But the Australian Industry Group says it hasn't seen any evidence of problems with part time employment arrangements, including the aviation industry. It accuses the union movement of using "the bogus scourge of job insecurity" and "an array of misguided interest groups and academics to pursue further workplace restrictions on businesses, particularly in relation to casuals". "In reality, there is no such problem," its submission to the Productivity Commission says. "The flexibility to engage casuals is critical for businesses as it assists them to better balance the supply of labour with demand for the businesses' products or services. The availability of casual employment is also critical for many employees who need or want the flexibility that casual employment offers." The Australian Industry Group said unions commonly but incorrectly state the Australian workforce is increasingly being casualised.

It says the proportion of people who work on a casual basis has been reasonably stable since 1998 at 19 per cent to 20 per cent of all workers. The proportion peaked at 20.9 per cent in 2007 then fell to 19.0 per cent in 2012 and was 19.4 per cent in November 2013. "Unions often erroneously claim that it is employers who are somehow forcing their employees to become casuals. While it is true that many employers need a mix of casual and permanent employees to provide necessary flexibility, in a large proportion of cases it is the employees who want to be casuals because they like the flexibility and the 25 per cent loading," the AIG submission says. "Many people prefer casual employment as it allows them to participate in the workforce when they would otherwise be unable to, and to better balance work with family responsibilities or study commitments." A spokeswoman for Qantas said there were peaks and troughs in workloads throughout the day, with more flights operating in the morning and later afternoon. "We need to make sure that the number of people matches the amount of flying that we do so that's why we use a mix of full time and part time staff to ensure we are operating efficiently and in line with the schedule," she said, adding that the "vast majority of Qantas workforce is full time".

A spokeswoman for the TWU said 1175 of 1290 Qantas Ground Services employees were part-time. Professor John Buchanan, director of the Workplace Research Centre at the University of Sydney business school said the issue was not whether the proportion of casual workers was increasing. One in five workers are casuals and miss out on working entitlements including training, paid holidays and the ability to get a mortgage. "The problem is not getting worse, the problem is now entrenched," Professor Buchanan said. "It is like saying the murder rate has stopped going up so we have to stop worrying about murders. If there are a lot of murders, you need to do something about them." Professor Buchanan said Roger Boland, as head of industrial relations at the Metal Trades Industry Association (which became the AIG), noted the rise in casual employment in the 1980s and 1990s and asked: "But is that what we want, a workforce of casuals?".