Figures from the WHO show that one in every 10 cigarettes consumed worldwide are illegal.
The UN health agency is warning the illicit trade of tobacco products is a major global concern when it comes to not only health, but economic, governance and corruption.
The WHO says the illicit trade undermines tobacco control efforts and leads to more smoking, as illegal tobacco makes the products more affordable and accessible, particularly to young people.
Vera da Costa e Silva is from the UN's Secretariat for the WHO Framework Convention on Tobacco Control.
"Illicit transactions are not subject to tax. It makes tobacco products less expensive and more accessible to children and young people. This has an impact on health and it also increases health costs."
Estimates suggest some 600-billion cigarettes worldwide are sold through the illicit trade every year, resulting in huge losses of tariffs.
The Council of Europe estimates the illegal trade in tobacco loses EU countries some 10 billion euros worth of annual tariffs.
Vinayak Mohan Prasad heads the WHO's smoking control unit.
He says African countries are most vulnerable to the impact of the illicit tobacco trade.
"Developing countries have a bigger problem because their systems are weak. So they want more support. They want more cooperation from other countries. It's a huge concern for African countries for example, because they lose a lot of money in taxes. They lose more since they need the money for development."
In a bid to consolidate the fight against the illegal tobacco trade, the signatories to the WHO Framework Convention on Tobacco Control have adopted the Protocol to Eliminate Illicit Trade in Tobacco Products.
So far, only eight countries, including China, have ratified the 3-year old protocol.
If ratified by 40 nations, the protocol will become international law.
The WHO says this would create a better guarantee for global cooperation in broader fight against smoking.
The WHO calling on all its member-states to speed up the process of ratifying the Protocol.
The World Health Organization says it views tobacco as the world's biggest-ever public health threat.
Estimates suggest smoking kills 6 million people a year.
Some 600-thousand die from diseases brought on by second-hand smoke.
The WHO estimates the annual death toll could rise to more than 8 million by 2030 unless urgent action is taken.
For CRI, I'm Zhao Jianfu.
