Yesterday, Ms Collins would not say what self-imposed industry limit she would deem acceptable.
"I would like industry to give it their best shot - I will not be telling them what should be included in the code. This must come from them."
She said if the industry's measures were not forceful enough or not working, the Government had regulation-making power to act within weeks.
Distilled Spirits Association chief executive Thomas Chin did not return calls yesterday. But the association, which represents a majority of RTD producers, has previously said it wanted a two standard drinks rule for all single serve beverages.
That would mean a 330ml bottle containing two standard drinks would have an alcohol content of about 8 per cent - a level of alcohol in many RTDs currently sold.
Yesterday, Alcohol Action NZ spokeswoman Professor Jennie Connor said self-regulation simply would not address the harm such drinks were causing.
"We can't expect the industry to behave in any other way, apart from to maximise their market," said Professor Connor, head of Otago University's department of preventive and social medicine.
"It's like putting the monkeys in control of the zoo ... What [the Government] is doing is based on special privileges, and wanting to maintain their political imagery."
Professor Connor said the Government's proposals in the Alcohol Reform Bill, which could come before Parliament next Thursday, were much too weak. The Law Commission, in a report the reforms were based on, said RTDs were commonly used by binge drinkers, and were the drink of choice for 14- to 24-year-olds, especially women.
The legislation originally proposed restricting RTDs to 5 per cent alcohol and limiting them to containers holding no more than 1.5 standard drinks.
At the select committee stage the cap on alcohol strength was raised to 6 per cent, and only restaurants and bars could sell higher-strength RTDs.
Ms Collins was lobbied by the managing directors of industry heavyweights Bacardi, Jim Beam, Brown-Forman and Diageo to allow self-regulation.
RTDs make up 12 per cent of the alcohol market by volume.