Police in Ivory Coast's commercial capital fired tear gas on Tuesday to disperse a crowd protesting a ban on plastic bags widely used throughout the country for water.

The protesters had gathered outside the prime minister's office in Abidjan and had begun to unfurl banners when police intervened firing tear gas and beating demonstrators with batons.

One person was injured and several others were detained.

The demonstration was called by the water sellers' union, which objects to a recent ban on the manufacture and circulation of plastic bags aimed at protecting the environment.

"A ban on plastic bags = death to 200,000 families," one banner read.

The sale of water packaged in little bags is widespread in a number of African countries.

"We want to work, we don't want to steal," one of the demonstrators, Joseph Koua, said while the smoke cleared.

"We don't want to die of hunger. We have gathered to protest at this untimely ... measure to ban the use of plastic bags," said Gervais Ekoun, leader of the union of authorised water producers in the west African nation, which groups 184 companies.

Ekoun added that the measuere will cause a loss in investment in plant and production material of some six million CFA francs (9.1 million euros, $11.4 million), as well as thousands of jobs.

The widely unpopular ban took effect in November and was among government measures intended to fight pollution and to promote a green economy, after a decision in May last year to get rid of plastic bags throughout Ivory Coast.

Streets in most Ivorian towns and villages are strewn with the small bags sold cheaply with water inside, then thrown away as in some other parts of Africa.

"We will continue to protest," Ekoun said, adding that the government should "take an alternative measure" to cope with a practice that is "40 years" old.