Speaking at the World Conference on Tobacco or Health in Abu Dhabi, Chan welcomed steps taken by several countries, led by Australia, to introduce plain packaging for cigarettes.
The WHO chief called for similar action by other nations.
Tobacco companies "use all sorts of tactics including funding political parties, individual politicians to work for them ... There is nothing they would not exploit to undermine the governments' resolve and determination to protect their own people," Chan told reporters.
Despite a decline in the number of smokers in many countries, more needs to be done to curb tobacco use to meet the global target of a 30-per cent reduction in consumption by 2025, participants said.
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"Largely thanks to legislative measures, smoking has plummeted in several countries," Chan told the meeting, referring to the latest WHO report showing that the proportion of men who smoke is going down in 125 countries.
Chan said non-smoking was "becoming the norm".
However, she urged countries that produce tobacco leaves to "move faster" to fight tobacco in cooperation with the Food and Agriculture Organization and the WHO.
The five-day conference aims to prove that tobacco use, in all its forms, is a major contributor to the occurrence of non-communicable disease (NCD) -- cancer, cardiovascular diseases, diabetes and chronic respiratory diseases.
Organisers warn that tobacco causes one in six of all NCD deaths and almost half of current tobacco users will eventually die of tobacco-related disease.
According to the WHO, one person dies every six seconds due to tobacco -- nearly six million people each year.
Smoking could kill one billion people this century, it says.
Participants at the conference have warned that unless urgent action is taken, the annual death toll could rise to eight million by 2030.
"Tobacco use is rising fastest in countries where control measures are relatively new," Chan warned.
China is "the number one country in terms of smokers, so it is important that China takes appropriate action to reduce tobacco consumption," Chan added.