Developing markets are fuelling an increase in cocaine trafficking through west Africa, the UN Office on Drugs and Crime (UNODC) said Thursday in a new report.

Seizures on the Atlantic island of Cape Verde, in the Gambia, Nigeria and Ghana contributed to a 78 percent increase in seizures from 2009-2014 compared to the previous period, UNODC regional representative Pierre Lapaque said at the report's launch in Dakar.

"Cocaine trafficking through Africa seems to be growing again and we have evidence of increasing trafficking to Asia and the Middle East," Lapaque said.

The European and North American markets were "saturated" with narcotics, the drug expert said, meaning criminal groups were looking further afield for expansion opportunities.

"Narco-traffickers have worked out that to develop their businesses, they have to position themselves in ," he said, adding that west Africa offered a young population with a middle class to sell to.

Lapaque said the link between drug lords and terrorists remained a disturbing feature of the market.

"We have learned that there are connections even if it is difficult to give figures," he said.

The UN-linked International Narcotics Control Board (INCB) said in March that Benin and Namibia were experiencing an increase in the number of wealthier drug users.

Despite this the global cocaine market appears to be "shrinking", according to the report, despite top producer Colombia recently massively upping its output.

Global coca cultivation fell by more than 30 percent between 1998 and 2014, due in part to nationwide efforts to eradicate the crop and alternative development programmes for affected farmers.