Men have worse habits than women when it comes to hand-washing hygiene, a Department of Health survey has found.
Fewer men than women admitted they were in the habit of always washing their hands after using the toilet, handling rubbish or sneezing, the survey of 2,001 people shows.
"I hope members of the public remember that even when your hands do not look dirty, it doesn't mean there are no bacteria on them," said Dr Anne Fung Yu-kei, assistant director for health promotion.
Of those interviewed during January and February, 9 per cent of men and 3 per cent of women admitted that they do not always wash their hands after using the toilet.
Dr Andrew Wong Tin-yau, the department's head of infection control, said that one gram of faeces, the weight of a paper clip, can carry a trillion germs.
He said that germs can survive for some time and not washing hands after using the toilet can contaminate the environment and other people.
The latest findings show that Hongkongers' hygiene standards are slipping, compared to a similar survey carried out in 2005.
The proportion of interviewees who said they always wash their hands after handling rubbish has fallen from 75 per cent to 70 per cent.
Those who said they cover their mouth and nose when coughing or sneezing dropped from 64 per cent to 57 per cent.
There was an improvement in the number of people who said they always wash their hands after coughing or sneezing, which increased from 31 per cent to 38 per cent.
In the recent survey, 31 per cent of women said they always washed their hands after touching public equipment while only 22 per cent of men did the same.
Also, more women than men said they would wash their hands before touching their eyes, nose or mouth.
The gender gap may be due to men being more careless, not realising when their hands are still covered with germs, Fung speculated.
That carelessness could contribute to the spread of disease. Wong called on the public to scrub their hands regularly and thoroughly - rubbing them with soap for at least 20 seconds.