New South Wales has become the first state to launch a complaints register publicly listing the companies which receive the most complaints to authorities, with real estate agent LJ Hooker topping the list.

Each year, NSW Fair Trading receives 50,000 complaints, but the data has not previously been made public.

The first list — of 20 companies — features real estate agent LJ Hooker with 31 complaints, retailer Harvey Norman with 29 complaints, and airline AirAsia with 25 complaints.

Only complaints that are deemed by case workers to be genuine and not vexatious are included.

NSW Fair Trading Commissioner Rod Stowe said all companies that received 10 or more complaints in a month would be named.

"It's open data, so it's information that has not been manipulated in any way and information I think the public are really deserving to know, in terms of the track record of businesses," Mr Stowe told the ABC.

"If you work in fair trading — as I have for over 20 years now — there's a whole lot of businesses you wouldn't want to engage because we know their track record.

"I think it's only appropriate the public also have that information available to them."

Got a confidential news tip? Email ABC Investigations at investigations@abc.net.au For more sensitive information: Text message using the Signal phone app +61 436 369 072 No system is 100 per cent secure, but the Signal app uses end-to-end encryption and can protect your identity. Please read the terms and conditions.

NSW Parliament last year passed legislation to make the information publicly available in monthly reports released online.

"We've engaged with all the traders we thought were likely to be on the list, those with a track record of large numbers of complaints over recent times," Mr Stowe said.

"Had we published the list in March when we issued the guidelines, we think there would have been about 30 businesses with 10 or more complaints.

"Interestingly, that list is only 20 because a whole lot of businesses have taken steps to improve their performance."

Real estate industry says register is 'flawed'

Four real estate companies are named on the complaints register, among a total of 20 companies.

Chris Mourd from LJ Hooker — which topped the list — said he supported a complaints register but that the system chosen was unfair and could mislead consumers.

"We're concerned that it doesn't represent or support the interests of consumers in NSW," Mr Mourd told the ABC.

"It doesn't clearly identify the individual offices that may have had a complaint registered against them that are part of a large group, whether that's a marketing body or a franchise group."

Rod Stowe dismissed criticism from the real estate industry that the register is "flawed". ( Supplied: Fair Trading )

He said the individual offices should be treated as separate businesses.

"By putting complaints under a master brand, they're just not identifying the businesses that are not doing well," Mr Mourd said.

Real Estate Institute of NSW chief executive Tim McKibbin said NSW Fair Trading had chosen the wrong model for its register.

"You may have an independent agent in your area that could end up with seven or eight complaints against them, and not get onto the register," he said.

"[Or] you could have a franchise agent in your area that is very competent and, in their own right, has no complaints registered against them, but unfortunately across the entire franchise group .. then that brand would be tarnished and the consumer misled."

'Entirely appropriate' to aggregate information under brand

But Mr Stowe dismissed the criticism.

"We think it's entirely appropriate that we aggregate that information under a brand — that's the brand the company advertises under," he said.

"People look to brands in terms of how businesses advertise.

"We've ensured that the guidelines we act under have been properly scrutinised, so the NSW Information Commissioner, the NSW Customer Service Commissioner and the NSW Small Business Commissioner have all looked to those guidelines and endorsed them."

Consumer group Choice said the idea of a complaints register should be rolled out in each state and territory.

AirAsia said it took customer complaints seriously.

"As a company operating in Australia, AirAsia is fully committed to high quality customer service and compliance with Australian laws," the company said in a statement.

"AirAsia takes customers' complaints seriously and provides our guests with various customer care channels ... We are also implementing additional measures to improve productivity and to add convenience and comfort to our guests' travel experience."

Harvey Norman has been contacted for comment.

The list can be found at www.fairtrading.nsw.gov.au.