The Gambia on Tuesday announced a ban on importing timber after years of accusations from neighbouring Senegal that it profits from illegal logging across their border.

Gambian loggers have long benefited from lax oversight of Senegal's southern Casamance forest to take prized rosewood timber over the border before exporting the logs to China.

The Gambia's Information Minister Sherrif Bojang told AFP "the ban on the importation of logs into the country is being enforced" following a presidential decree on the topic last week.

"The security personnel manning the borders are instructed not to allow any log to enter the country," the decree read.

However ecologist Haidar El Ali, a former Senegalese environment minister who spearheads the movement to protect Casamance's forests, said he thought the move was simply a short-term strategy by President Yahya Jammeh.

"I think it's a just a big charade in the run-up to the elections, where he is under a lot of pressure," El Ali told AFP.

Jammeh is seeking a fifth term in power to extend his 22-year rule over the country, but faces an unusually united opposition at the election in December.

"He wanted to make a show because the farmers are complaining about the exhaustion of their soil," a result of deforestation, the former environment minister said.

"(Jammeh) organised this trafficking and he has profited from it himself," El Ali added, accusing the president of benefiting from the activities of WestWood, the only company authorised to export logs from the Gambia.

Chinese traders purchase timber from Gambians who source the wood from Senegal, often with the connivance of impoverished local populations in Casamance.

Exporting timber is illegal in Senegal, which surrounds Gambia's narrow slither of territory in west Africa.