The conference was focussing on the marketing of alcohol products.
Professor Casswell said that mostly unregulated advertising for alcohol products allowed companies to shift their target audience easily.
"It would be much harder for them without marketing to move into these other areas.''
If marketing was banned altogether, the industry would still be successful but consumption levels and the number of young drinkers was likely to fall.
Prof Casswell said the alcohol industry's other emerging market was in developing countries where incomes were low but regulation was light.
"The marketing there is doing an essential job for the industry to penetrate through the population as quickly as possible to persuade them to be sophisticated alcohol consumers.
"They know the race is on. They know those governments will in time put in place more effective policy.''
The conference was hosted by public health lobby group Alcohol Action NZ.