Opponents of the proposals say they will also impose restrictions on the size and shape of cigarette packs and bigger health warnings.
The plans for rolling tobacco would have significant impact in the UK, where 77% of sales are of packs of 25g or under, according to Imperial Tobacco.
Head of corporate and legal affairs Colin Wragg said: “Retailers will lose a valuable part of their revenue and adult smokers‘ choice will be reduced.
“Coupled with lost sales due to illicit tobacco trade this represents a double whammy.”
Wragg added that a ban on sales of cigarettes in packs of less than 20 sticks would mean “enforced supersizing”, running counter to attempts to engineer consumer habits towards more healthy consumption in sectors such as soft drinks and chocolate.
“The entire tobacco supply chain, but especially the hard-working retailer, will be severely affected if this regulation is enforced,” Wragg said.
Angela Harbutt, campaigns manager at smokers’ lobby group Forest, added: “Consumers will be driven to the black market where there will be a flourishing trade in banned goods.”
The organisation has launched an online petition against the plans at NoThankEU.com.