The Chows' Mermaids strip bars were dens of drunkenness, carefully calculated and promoted by the businessmen brothers to prise as much money as possible from patrons' pockets, a tribunal has heard.

Former employees - strippers, waitresses, prostitutes and managers - laid bare the brothers' business methods at the Alcohol Regulatory and Licensing Authority in Auckland this week.

With their flights and accommodation to appear at the tribunal paid by rival strip club Calendar Girls, the former employees, whose names are suppressed, detailed claims of sexual assaults going unpunished, methods of making patrons so drunk they did not know what they were spending, and measures taken to hide the system from police.

Wellington was said to be "far worse" than the Chows' Auckland operation.

The brothers' lawyer says they have run several businesses for more than 12 years and the evidence presented against them is an effort to eliminate a competitor.

Among allegations by former staff to the tribunal:

Waitresses were expected to sell 10 shots a night under threat of losing shifts. Lap dances were marketed as coming with a free bottle of sparkling wine - "If a customer was borderline [drunk] then they would get their bottle . . . because nobody wanted to miss out on a sale."

When men passed out they were left and billed for the time they spent - one said he had $2200 taken from his account while he was asleep.

The Chow brothers were seen in the establishments drunk. (John Chow told the tribunal he slept with the prostitutes he employed.)

The private rooms used for lap dances and the brothel rooms were utilised to hide the most drunk patrons from police. Bouncers would go into "overdrive" shifting the intoxicated from the bar into private rooms or upstairs to the Splash Club brothel when police came to do checks.

A girl was found passed out in the bathroom and a former duty manager called an ambulance. "A duty manager said to me, ‘you should've told the ambulance that we found her on the street'," the former duty manager said.

Sexual assaults were common at Mermaids "because the bouncers would not stop anything".

Staff were also encouraged to drink and the strippers would sometimes get so drunk they threw up.

A prostitute described working at the Splash Club as a "nightmare experience". The sex workers were fined for being late and fined if they refused to service a client, even if the client was drunk and abusive, she said.

When a customer passed out she was sometimes encouraged to get another girl so he could be charged for both of them.

The evidence of how the Chows' clubs were run was presented by lawyers for Jacqui Le Prou, the owner of Calendar Girls which is opposing Mermaids' Auckland alcohol licences.

Most of the witnesses said Ms Le Prou had paid their flights and accommodation to Auckland to testify and John Chow said she had advertised on Facebook for people to give evidence.

John and Michael Chow have applied for liquor licences at their clubs in Gore St, central Auckland, and the newly opened site on Karangahape Rd.

Calendar Girls moved into Auckland and Wellington after the Christchurch earthquake and Mermaids and Calendar Girls are both in Karangahape Rd.

Calendar Girls in Wellington, which is in receivership, lost its liquor licence after opposition from the Chows.

The brothers' property portfolio is large but it is their Il-Bordello and Splash Club brothels and Mermaid strip bar that are most well known in the capital.

Their lawyer, Alistair Sherriff, told the authority that the brothers' applications were not opposed by the district licensing inspector, police or the medical officer of health, but a single objection has been registered by Casino Bar No 2 - the company Le Prou co-owns with Aaron Greenwood.

Sherriff urged the authority to see the evidence presented as an effort to remove a competitor.

Judge John Hole reserved his decision.