"This is an industry that sells a product that kills up to half their consumers," but companies are still able to draw in a new generation of smokers despite measures in a 2005 tobacco-control treaty, he said.
"Most tobacco users start their deadly drug dependence before the age of 20," he told reporters, ahead of Friday's World No Tobacco Day.
"Banning tobacco advertising, promotion, and sponsorship is one of the best ways to protect young people from starting smoking as well as reducing tobacco consumption across the entire population," he added.
Bans on overt advertising are crucial, he said, but companies are masters at finding less-obvious means to attract potential smokers and ensure customers remain loyal.
"Tobacco companies are like a mutating virus. When you ban one type of advertising, maybe the most commonly-known forms, billboards, television, radio, they move into other areas," Bettcher said.
He pointed to tactics including selling branded products such as clothing, product-placement in reality TV shows, using social media to fuel a sense of consumer community, and event sponsorship.
"That's why the ban has to be complete in order to be fully effective," he said.
Bettcher noted that as of 2011, 19 nations had introduced total bans -- and seen a seven-percent reduction in tobacco use -- while one-third of countries had minimal or no restrictions.
Fresh data are due in July.
With increasingly-tough measures in developed nations, tobacco firms have moved to drive up demand in markets such as Africa.
Bettcher warned of a "perfect storm" on that continent, with health services even less able to cope with the impact of smoking than their developed-nation equivalents.
Bettcher also lauded Australia for its landmark plain packaging rules, in force since December, which require tobacco products to be sold in drab-green boxes bearing the same typeface and graphic images of diseased smokers.
New Zealand and Ireland have announced plans to follow suit, despite a tobacco industry-backed challenge to Australia at the World Trade Organization by cigar-producers Cuba, Honduras and the Dominican Republic, plus Ukraine.