ABIDJAN, June 25 (Reuters) - Only small amounts of Ivorian cocoa have been smuggled in recent weeks to neighbouring Ghana where the product fetches almost $0.90 per kilo versus $0.32 or less in Ivory Coast, trade sources said.

Estimates of May/June volumes smuggled are difficult to get, but one source said the illegal transit of Ivorian beans to Ghana seemed to have boosted April arrivals in Ghana by around 5,000 tonnes.

``It is done by bicycle and bag-by-bag,'' said one source.

A London-based West Africa cocoa crop analyst confirmed that volumes of Ivorian cocoa smuggled into Ghana were relatively small as he believed big trucks would be intercepted by Ghanaian customs officers.

``On the Ghanaian side they are fairly sharp on that and as they keep on moving around their customs officers from one border post to the other, smugglers have a hard time bribing trucks through,'' the analyst said.

Ahead of liberalisation of its cocoa sector, by October 1, farmgate prices in Ivory Coast have started following world market trends and are down to 200 CFA francs ($0.32) per kilo from the official minimum reference price of 455 CFA per kilo.

In Ghana, farmgate prices are still rigorously maintained at the 2,225 Cedis per kilo ($0.90) fixed by the Cocobod cocoa board at the start of the 1998/99 season (October-September).

As the quality of Ivorian beans is inferior to Ghanaian beans, the smuggled beans are mixed in with Ghanaian beans by farmers before being sold to Cocobod's produce buying company or a private cocoa buyer.

Ghana has liberalised internal marketing but maintains strict upcountry quality controls.

``Cocobod officials said that they were going to put in place even stricter checks in border areas to try and stop farmers diluting their beans with poor Ivorian ones,'' said one international crop analyst.

Smuggling between Ivory Coast, the world's top producer of cocoa, and neighbouring Ghana and Guinea, happens every year and -- depending on the prices -- in either direction.