Kenya's police boss has said the grace period for everyone to wear masks has expired and arrests will now take place, starting on Wednesday.
Inspector General Hillary Mutyambai said people had been given enough time to buy the masks and enforcement will now start.
The ministry of health gazetted that anyone found without a mask will be fined Ksh20,000 or face a six months jail term.
Public transport operators had earlier asked the government to supply them with masks citing high costs.
Currently, a single-use mask is retailing at Ksh100 while an N95 version retails for up to Ksh1,500.
The government had issued a directive that everyone in public places wears a mask and contacted various companies to help in the production of masks.
The ministry has been running public education on how to wear and remove masks to ensure no contamination takes place.
Since the start of the coronavirus outbreak, the official advice from the World Health Organization has been clear.
Only two types of people should wear masks: those who are sick and show symptoms, and those who are caring for people who are suspected to have the coronavirus.