A decision by a South African court to hold a Moroccan ship laden with phosphate mined from the disputed Western Sahara pending a trial, has been condemned by Morocco.

The court said it wanted to determine ownership of the cargo of the boat that is being held at Port Elizabeth.

The 34,000-tonne vessel from Western Sahara, which was destined for New Zealand, was last month prevented from departing due to a court motion seeking that the vessel return its cargo.

The motion argued that the transportation of goods from disputed Western Sahara is illegal and in violation of international principles.

"The court has basically found that the Saharawi Arab Democratic Republic and the Polisario Front have established, on a prima facie basis, that effectively the people of Western Sahara own the cargo," Andre Bowley, the complainants' lawyer told AFP.

But Otmane Bennani Smires, legal director of the OCP group, a global market leader in the phosphates industry, said the firm "contests the decision to send the case to trial".

The OCP, on its website, said that the court's decision "directly contradicts and damages the internationally supported United Nations negotiating process" between Morocco and the Polisario Front.