Over 30 percent of lung cancer patients in Japan who have jobs are exposed to passive smoking at workplaces, underscoring the need for legal action to reduce the risk at offices and public places, according to a patient support group.

The Japan Lung Cancer Alliance said a recent survey found 31.7 percent of 123 patients had been subjected to secondhand smoke at work and 5.2 percent said they had quit jobs to avoid passive smoking.

The survey was conducted among 215 patients via the internet between May and June.

The occupational safety and health law urges businesses to make efforts to prevent passive smoking at workplaces, but sets no penalty.

Ahead of the 2020 Tokyo Olympic and Paralympics, the government wants to begin penalizing operators of businesses and public facilities for failing to prevent passive smoking. But the ruling Liberal Democratic Party and the health ministry remain at odds over legislation to do so.

The health ministry estimates about 15,000 people die annually in Japan from diseases caused by passing smoking.

"A number of patients are exposed to life-threatening risks on a daily basis," said the group's head Kazuo Hasegawa, calling for a strict crackdown.