Australia faces a potential challenge to its laws through the World Trade Organization, with three tobacco growing countries - Ukraine, Honduras and the Dominican Republic - making official requests for consultation on plain packaging. Consultations are the first stage of the WTO's dispute resolution process.
These countries argue that the laws contravene Australia's international obligations in respect to trade-related aspects of intellectual property.
Roxon said while countries had raised with Australia the trade implications of the laws, her government would fight to maintain them.
"It's never been asserted successfully around the world in any trade dispute that governments are not allowed to take public health measures to protect their community," she said.
Ross McKenzie, a Macquarie University lecturer on health studies, said it was likely that the tobacco industry was behind the WTO challenge.
"From everything I've read, the challenges won't be particularly strong," McKenzie said.
"The trademarks aren't being expropriated; they're being restricted in their use, which is quite different. There're lots of trademarks that are restricted by lots of governments," he added.
Tobacco advertising was banned from Australian television and radio in 1976. Restrictions on advertising have tightened over the years to include print ads, the Internet and retail outlets.
Smokers account for 17 percent of Australia's population, compared with around 20 percent of American adults.
With high taxes aimed at dissuading smokers, a pack of 25 cigarettes retails in Australia for about 16 Australian dollars ($17).
Associated Press writer Kristen Gelineau in Sydney contributed to this report.
The Associated Press