Three Ghanaians were arrested at Accra airport earlier this week after 30kg of cocaine was found in a cargo container at Johannesburg International Airport, police said.

South African police spokesperson Inspector Diane Mars said South African police allowed the cocaine - with a street value of R16.5m - to be transported to Accra airport as it was meant to.

Police monitored the consignment and arrested three Ghanaians when they went to collect the cocaine on Monday.

The cocaine was discovered in a cargo container on an aircraft from Sao Paulo at Johannesburg International Airport on Friday.

The drug was concealed in a piston cylinder of a car and the handle of a butcher's knife, was found during a routine inspection by the cargo drug team.

The three men would appear in court in Ghana.

She said Johannesburg was merely used as a transit point and no arrests were made locally.