A public health expert on Friday called on Hong Kong authorities to investigate anyone selling cheap cigarettes, to crack down on the smuggling of tobacco into the SAR.

Daniel Ho, from the University of Hong Kong's School of Public Health, said importers reportedly mix un-taxed cigarette cartons in with ones on which duty has been paid.

The Hong Kong Council on Smoking and Health member told RTHK that to discourage smuggling, the government could implement a minimum pricing policy on tobacco, and clearly label duty-paid cartons.

"Immediately what the Customs and Excise Department can do is to launch a high-profile investigation into retailers selling cigarettes at below cost," Ho said.

He added that this is "essentially a confession of duty not paid, and a blatant challenge and insult to the department."

The investigation should then be extended to look at any cigarettes being sold at suspiciously low prices, he said, adding that the authorities should also trace the illicit cigarette supply chain.

Ho said in the longer term, the government could consider imposing minimum pricing on tobacco products "to make illicit cigarettes less competitive at legal point of sale."

The Secretary for Health, Lo Chung-mau, said on Saturday that a marker could be lasered on individual cigarettes to signify that duty had been paid on them.

Ho said this would "greatly help" retailers and customers to identify illicit tobacco products.