Cigarettes that come in one-color packets taste worse and are dominated by vivid health warnings, smokers claim.
Advice group Quitline and Facebook fan sites have been inundated with comments saying their smokes taste 'pathetic', 'sickening' and 'lack flavor'.
Tobacco companies have denied changing ingredients, while pundits say the issue highlights the power of branding, the Telegraph reports.
A spokeswoman for Imperial Tobacco Australia, which makes Peter Stuyvesant, Davidoff, Horizon and Camel, said the company had 'not changed any of our tobacco products'.
British American Tobacco, which makes Winfield, Benson and Hedges and Dunhill, also denied changing the makeup of their cigarettes.
According to the paper, Action on Smoking and Health's Anne Jones said the complaints showed why the government was right to target the branding of cigarettes in its bid to drive smoking rates down.