Brazil is increasingly the source of cocaine seized in the Belgian port of Antwerp, Europe's main entry point for the drug, overtaking the world's biggest producer Colombia, according to customs data published Thursday.

So far this year, up to September 25, authorities have confiscated 40.7 tonnes of cocaine in the port, with a quarter of it - 26% - coming from Brazil, Belgian customs service figures showed.

The proportion coming from Colombia fell to 13%, from 50% last year.

The figures showed that Ecuador had also become a primary source of cocaine, with 20% coming from that South American country.

Costa Rica also figured in the data, accounting for 16% of the cocaine seized in Antwerp.

Florence Angelici, a customs spokeswoman, told AFP the figures in part indicated that law enforcement in South American countries were becoming "more proactive" in checking consignments for smuggled drugs and informing Belgian authorities.

But generally, the shift showed that cocaine trafficking had become more internationalised, with countries neighbouring Colombia increasingly being used as platforms to get the drug to Europe.

"The cultivation and production in Colombia increased significantly in the past five years. All neighbouring countries seems to be impacted," the statement said.

Brazil was especially problematic. The vast nation is home to many criminal gangs and has many sea links to Europe. 

"We in Europe do everything we can to enhance the cooperation and information exchange with Brazil," the Belgian customs service said, adding that a memorandum on the issue was signed recently with Brazilian counterparts.