The CTU released an independent report by BERL, written by economist Ganesh Nana, which noted that the OECD-favoured sector-wide bargaining because it "provides sufficient flexibility for productivity growth while enabling a broad sharing of gains".
"Evidence over 20 years indicates that under the right conditions, the impact on a nation's economic performance of collective sector wage bargaining is no better or worse than that from individual contract negotiations," the report said.
The Government is currently considering Fair Pay Agreements after receiving a report from a working group, led by former National Prime Minister Jim Bolger, in January.
The group recommended that workers in a sector could trigger Fair Pay Agreements in a sector if they met a minimum threshold: 1000 people or 10 per cent of workers in the sector or occupation, whichever was lower.
A majority of the working group said it should be compulsory for employers to be part of an agreement.
Business groups and the National Party have attacked the agreements as potentially hurting the country's productivity.
"It would be a drastic movement away from a flexible, strong workforce ... forcing small business, medium-sized businesses into what unions and the Government want them to," National leader Simon Bridges said this morning.
"National will never agree to that."
But Ganesh said other factors such as investment in skills and training had a far bigger impact on productivity, and whether employment contracts were individual or collective ones was "not that important at all".
CTU economist Bill Rosenberg said that wages in the cleaning, security and supermarket sectors had fallen below 1981 levels in real terms.
He said workers had not had a fair share of the country's economic growth, and changes to employment contract law had gutted union movements, seeing wage growth fall well behind productivity growth.
If wages had kept up with productivity, he said the average hourly wage would have been almost $8 an hour more than it was in March 2018.
CTU secretary Sam Huggard said employers in the cleaning, security and supermarkets sectors had indicated supportive for Fair Pay Agreements depending on what the Government proposed, including the Building Services Contractors, the NZ Security Association, and Countdown.
Kiri Hannifin, Countdown's general manager of corporate affairs, said she was waiting for the Government proposal until assessing how it might impact Countdown.
Building Services Contractors chief executive Sarah McBride said the organisation represented about 30 commercial cleaning companies and 10,000 of the 26,000 workers in the sector.
She said Fair Pay Agreements that would bind all employers would level the playing field and stop her workers being undercut by subcontractors and franchises.
"One of my members has lost some Government business recently - for 50 cleaners - and were told over the course of a three-year contract this other subcontractor was $860,000 cheaper than them.
"My member doesn't want to go public with that because they're hoping to win the business back. This dynamic is ruining our sector."
Sinoti echoed this sentiment, saying that her job security was at risk when other contractors came in and her hours were cut.
She has now taken a different cleaning job, working 44 hours a week, but previously worked a 55-hour week, which barely covered rent, food, and power and phone bills.
"Whatever is left, and then I try to spend [on] my kids' clothes, my kids' gears for school."
Workplace Relations Minister Iain Lees-Galloway welcomed the BERL report and said the Government was still working on the policy design of Fair Pay Agreements.
He did not give a timeline on that work but said NZ First was not holding it up, and the Government's proposal would eventually go out for public consultation.
New Zealand First has previously put the brake on Labour's plans for overhaul the workplace relations landscape, but Huggard said New Zealand First had good reasons - such as reducing inequality - to support Fair Pay Agreements.
Bridges said he expected the Government to pull back from Fair Pay Agreements.
"It's not going to happen. That's why the unions are starting to jump up and down because Jacinda Ardern, just like with the capitl gains tax, just like with some of the bigger employment law reforms they promised and haven't gone through with, they won't go through with fair pay [agreements] either."
