Zero hour contracts are now illegal but some fear new ways of taking advantage of workers are taking their place.
The insecure contracts were outlawed in March but, according to unions and some low-paid workers, businesses looking to cut costs and reduce commitments are now doing so by hiring staff at arms-length - via temping agencies or labour-hire companies.
Pass through somewhere like Auckland International Airport and you'll see them everywhere, but probably not notice: labour-hire contractors, working for the various companies that keep this transport hub for this country's largest city moving.
As I waited to get off a plane in the early hours of a damp winter's morning, workers were buzzing around the tarmac delivering airline meals from flight kitchen to aircraft. And, wheeling my suitcase through to be X-rayed, workers at all three conveyor belts were wearing polar fleeces with company logos - not those of the Ministry for Primary Industries (MPI), but of labour-hire agency Adecco.
Some of those temporary workers might be filling in here and there, covering someone's sick day or be grateful to get a foot in the door of an industry they want a permanent job in.
But MPI said some of its roles, including those of safety officers, who assist X-ray machine operators at airports by lifting baggage onto conveyor belts and opening them for inspection, were carried out only by labour-hire workers.
The ministry said that was because it was cheaper to employ contractors on an as-needed basis to do the work.
But unions are concerned that casual contracts that stretch on into years are becoming more common, and they are being used to exploit low-paid workers, many of whom are immigrants.
By not having workers as permanent staff businesses can save on some sick leave, overtime payments and pension savings. They can also cut risks; as business fluctuates, they can stop employment with no questions asked, even if people have been working for them for years.
Shopan Dasgupta, an organiser for E Tū's hospital and flight-kitchen members in Auckland, said labour-hire companies had gone from providing genuine temporary job opportunities to providing an opportunity for companies to exploit workers by distancing themselves from their responsibilities to provide, fair, safe and secure work.
"We want to prove that they are actually your employees, and you cannot fob them off as and when you wish," he said.
He is currently dealing with a case involving several workers who took up roles in catering and transport for LSG Sky Chefs via labour-hire company Solutions Personnel, also now operating under company name Blue Collar.
Sky Chefs, which makes in-flight meals, is part of German airline Lufthansa, and one of its former agency workers, Kamlesh Prasad, is taking a case to the Employment Court claiming the company was his employer.
As a new migrant to New Zealand from Fiji, with little knowledge of how employment in this country worked, he felt he was duped by LSG Sky Chefs and its labour-hire company into signing himself up as an individual contractor, when he thought he was actually working via the labour-hire company.
"They pay me $18 per hour, no holiday and no sick pay, nothing like that. If I asked LSG to pay they just say 'you are a contractor so you just go and talk to your agency'."
Out of his $18 per hour pay packet, Mr Prasad had to pay for his own safety boots and some equipment, and about $960 for his annual ACC levies. He even had to pay his agency a dollar to get a copy of his payslip sent to him, he said.
Labour Inspectorate general manager George Mason said that sounded unlawful.
"The Labour Inspectorate clearly could investigate that and take enforcement action. Employers are required to provide records to their employees as of right - there's no provision for charging for that kind of information."
Solutions Personnel, now Blue Collar, did not respond to Insight's request for an interview.
LSG Sky Chefs declined to be interviewed but said in a statement:
"LSG Sky Chefs is an ethical employer that meets its legal obligations in its use of labour supply. It is committed to ensuring that it complies with all legal obligations for its employees, contractors and service providers.
"To meet demand, LSG Sky Chefs, like many other New Zealand businesses and service industries, utilises casual labour hire, supplied by external service providers, so it can continue to deliver a consistent and seamless service to all its customers.
"LSG Sky Chefs values its workforce including its temporary labour hire. Its preferred supplier agreement provides for benefits like sick leave and KiwiSaver contribution.
"As Mr Prasad's case is currently before the court, it is unable to comment on this any further."
Simon Bennett, the chief executive of AWF Madison, which owns labour-hire company Allied Workforce, said the valuable role labour-hire companies played in getting people work-ready was too often ignored.
"The reality is, there are kids out of school, there are young people who are new to the country that have perhaps done study but need a chance - and not all employers, despite the 90-day [trial] rule, will take the risk on new starters with no experience."
But Labour workplace relations and safety spokesperson Iain Lees-Galloway believes temping contracts are being abused.
"Some [businesses] are extending it into something it was never meant to be when temping agencies were first set up, and using it to make the employee carry all the risk of business. And in that way it's not unlike the zero hours contracts," he said.
Workplace Relations Minister Michael Woodhouse declined Insight's request for an interview about labour-hire companies.
A spokesperson from his office said the minister felt it wasn't appropriate to comment on the unfairness of unwanted long-term casual contracts because they were not illegal.
Temporary workers who feel they are being exploited can call the Labour Inspectorate at the Ministry of Business Innovation and Employment on 0800 20 90 20.