Illegal tobacco worth a street value if over £140,000 has been seized since April 2014 as part of the Tackling Illicit Tobacco for Better Health Programme.
The scheme, which operates in Leeds, Bradford, Calderdale, Kirklees, Wakefield and City of York Council, has received over 1,000 intelligence reports and made 349 enforcement visits.
There have been 26 criminal prosecutions and 11 ongoing investigations.
David Lodge, head of West Yorkshire Trading Standards, said: “Our message to sellers is clear: we will come down hard on anyone selling illegal tobacco. Our enforcement efforts are only going to get more intense and more focused.
“Fines for selling illegal tobacco are unlimited and can result in up to 10 years in prison. We are continuing to act on intelligence passed to us by the public, and we are still urging smokers to think about the impact local illicit sales have on enabling children to smoke before they can legally buy.
“If you don’t want local children to smoke, and you know where illegal tobacco is being sold, we would encourage you to get in touch and report it anonymously.”
Councillor Pauline Grahame, deputy chair of the West Yorkshire Joint Services Committee which oversees the work of Trading Standards, said: “Smoking rates in the UK are declining.
“Reducing the supply and demand of illegal tobacco is one important element of a comprehensive approach to tackling tobacco harm in communities.
“It is key to addressing smoking-related health inequalities and poverty, playing a key role in preventing young people from starting to smoke.”
The YEP revealed last month more than 26,000 illicit cigarettes were seized in raids on seven shops in Leeds.