As the NSW government continues to stall on the new licensing reforms promised three years ago, the spread of illegal parlours is now so prolific north of the harbour that they have crept into some of Sydney's wealthiest suburbs, including Neutral Bay and Cremorne.

And, two years after they were ordered to shut down to prevent the exploitation of women, Fairfax Media can reveal 15 illegal brothels continue to operate daily from the same premises across Chatswood, Willoughby and Artarmon.

Concerns have also been voiced about the emergence of a series of restricted adult forums where thousands of ''punters'' not only review sex workers but share tips and stories on how to ''crack'' illegal Asian workers who will not have sex.

Chris Seage, who runs Brothel Busters, which investigates illegal brothels on behalf of councils and the legal brothel industry, said: ''When existing laws were introduced six years ago, councils were handed the power to close illegal brothels within five days. Yet, according to latest evidence, they seem unable to stop them altogether. A brothel closure order is not worth the paper it's written on. The lack of follow-up action is appalling.''

As of last week, there were at least 19 illegal brothels in the Willoughby council area and another 15 in the North Sydney Council area. Some are in view of schools while others occupy street space alongside high-end restaurants and retail traders in prime commercial zones, including Military Road and Chatswood.

''These dodgy operators are setting up on the north shore because of its affluence,'' Mr Seage said. ''The trend has now reached epidemic proportions and nobody, from any tier of government, knows how to stop it.''

In 2007, the NSW government introduced a range of reforms under the Restricted Premises Act to help Sydney councils better detect and prosecute illegal brothels. The then premier, Morris Iemma, also handed local courts the power to shut down electricity, gas and water supplies.

But, in the years since, cash-strapped councils have found the system hard to enforce. Once a suspected brothel has been found, councils must hire private investigators to collect evidence. After a brothel closure order has been served, councils must also monitor the premises to ensure it has ceased operating. If a court order is to be obtained, the costly, time-consuming cycle must start from scratch.

While hundreds of illegal Sydney brothels continue to fly under the radar by masquerading as health, medical and remedial massage centres, they are being exposed by a growing number of clients, or ''punters'', who ''rate'' sex workers on brothel review forums.

In 2011, Willoughby Council served brothel closure orders on 21 illegal premises. However, searches across websites such as ''Punter Planet'', ''Hooker Looker'', ''Aus99'' and ''Australian XXX Reviews'' show all but six are still thriving.

The North Shore Oriental Health Centre, on Penshurst Street, was reviewed as recently as last week. One member, who identifies a worker by name and describes her as being a ''little fat around the middle'', boasts to fellow punters how she got him ''over the line'' while another writes of the same woman: ''Full Service 7.5/10 … All in all $90 well spent.''

Willoughby City Council general manager Nick Tobin said the council was aware of several illegal brothels but the process of trying to keep them closed was ''time-consuming and costly''.

''Present legislation puts the onus on councils to identify the illegal brothels and chase them until they stop,'' he said.

Referring to ''discussion'' about a NSW government licensing system similar to that imposed on pubs and clubs, he said: ''We would certainly welcome more support … but I'm not sure how a licence scheme can solve anything. Illegal brothel owners and sex traffickers do not want to apply for development applications or comply with laws. It's as simple as that.''

On Thursday, North Sydney Council confirmed that its compliance team was launching legal action against seven premises, previously identified by Brothel Busters, found to offering illegal services. However, customer review sites show there are at least eight more doing business.

Crows Nest, in particular, is now so rife with illegal brothels, clusters are developing.

On one Pacific Highway corridor, three sit within just metres of one another. One of those, VIP Bodycare, is directly above a furniture store.

The building's owner said: ''I know little about what goes on upstairs. A real estate agent handles the rent.''

Special Minister of State Chris Hartcher, who has been promising a new brothel licensing authority since 2010, said the government was working to ''curb the proliferation'' of illegal brothels. He said an issues paper had been ''developed'' and options were being ''finalised''.