They can be smelly, dirty and full of germs, but 20 per cent of smokers light up in public toilets, reported a survey.

Smokers said they wanted to save time by multi-tasking in the toilet. The majority of such smokers would also dispose of their cigarette butts in the toilet bowl.

The most common locations where smokers left a trail of their behaviour - like cigarette burn marks or stubs - were the toilets at coffee shops, followed by those in pubs and clubs, observed non-smokers in a separate poll.

To discourage smokers from lighting up in public toilets, pharmaceutical firm Pfizer and the Restroom Association of Singapore will be implementing a public awareness drive.

From December, all 24,500 public toilets across Singapore will display posters underlining the hard of nicotine addiction. Smokers would also be encouraged to quit the habit by calling a Health Promotion Board Quitline via these posters.

In Singapore, more than seven people die a day from smoking-related diseases.