Burundi says from next week anyone caught using plastic bags will be punished, bringing forward a deadline to phase them out by six months.
The government banned their use last August, allowing an 18-month period for consumers and retailers to finish their stock.
But Environment Minister Déo-Guide Rurema said he had taken the decision to impose the ban from 22 August as plastic bags were still being used so widely.
He did not specify what punishment those who break the ban will face.
At a press conference in the main city of Bujumbura on Tuesday, the minister held up a paper bag and said locally produced, environmentally friendly bags should be used instead.
Yet locals told BBC Great Lakes that the paper bags were not easy to find.
Several countries in the region have taken action against plastic bags, including neighbouring Rwanda, which banned them in 2008, Kenya, which prohibited them in 2017, and Tanzania that stopped their import in June.
The United Nations Environment Programme says 63 countries around the world have banned or taken measures against the use of plastic bags.