The Ministry of Health and Welfare is considering forcing cigarette companies to label toxic chemicals and their quantities on cigarette packets, news reports said Tuesday.

If implemented, it would be the nation’s strongest-ever antismoking warning on cigarette packaging.

“The ministry is considering a new management system for cigarettes, which calls for indication of ingredients and their quantities on the labels in a move to control toxic chemicals,” a ministry official told a local daily.

“Because cigarette ingredients are not expressed sufficiently on the packs, it has been difficult for citizens to understand the hazards of smoking precisely,” said the official.

A related law requires tobacco companies to indicate the presence of nicotine and tar on cigarette labels. The law allows them to label only six other carcinogens, including nikel, benzene and arsenic, without specifying their quantities.

A cigarette is believed to contain at least 250 harmful chemicals, more than 50 of which can cause cancers in the mouth, brain, lung, breast, bladder, stomach and other parts of the body.

With the measure, the government seeks to get tough on smoking, but the move faces bleak prospects of passing the National Assembly, as lawmakers have previously failed to agree on stronger antismoking measures.

In April, members of the parliamentary health and welfare committee failed to narrow differences about the adoption of graphic health warning labels, which are already in use in Britain, Singapore and other countries.

Meanwhile, Seoul City, marking the May 31 World No Tobacco Day, announced Tuesday that a smoking ban at Seoul Plaza, Cheonggye Stream and Gwanghwamun Plaza would take effect from June 1.

Those caught smoking in any of the three areas will be fined 100,000 won ($93), the city said.

City officials will patrol the areas from 9 a.m. to 7 p.m. every day and ticket smokers on the spot using mobile devices.

The city designated the three areas as non-smoking zones on March 1, and has conducted a promotional campaign over the past three months.

According to a survey last year, Korea has one of the highest adult smoking rates among OECD nations. Its adult smoking rate was 40 percent, more than double 17.9 percent in the U.S.

By Lee Ji-yoon (jylee@heraldcorp.com)