CUBA has become the latest country to launch a legal attack on Australia's landmark plain packaging rules for tobacco at the World Trade Organisation, the global body says.

The WTO said that Cuba had requested consultations with Australia on law requiring tobacco products to be sold in identical, olive-brown boxes bearing the same typeface and health warnings with graphic images of diseased smokers.

Under the 159-nation WTO's rules, requesting consultations is the first step in an often complex trade dispute settlement process which can last for several years.

Given that the legislation covers all tobacco products, not just cigarettes, it has already been challenged at the WTO by Cuba's fellow cigar-producing nations Honduras and the Dominican Republic.

In addition, Ukraine has filed a suit at the Geneva-based body, which oversees its member nations' respect for the rules of global commerce.

All the plaintiff countries maintain that Australia's packaging law breaches international trade rules and intellectual property rights.

In the event that the WTO's disputes settlement body finds in their favour, it would have the power to authorise retaliatory trade measures against Australia if the country failed to fall into line.

The dispute with Australia marks the first-ever challenge by Cuba against a fellow member since it joined the global body in April 1995, four months after the WTO was founded in its current form.

The legislation - passed in 2011 and brought into force last December - has won wide praise from health organisations which are trying to curb smoking.

The Australian government has faced a string of court challenges from tobacco firms.

Besides trade and intellectual property concerns, tobacco companies say there is no proof that plain packaging reduces smoking and have warned that the law sets a precedent that could spread to products such as alcohol.

New Zealand has announced plans to bring in its own plain packaging law this year, making it only the second country in the world to do so.