Iraq's supreme court on Monday ordered the suspension of a September 25 referendum on the independence of Iraqi Kurdistan, to examine whether such a poll would be constitutional.

"The supreme court has issued the order to suspend organising the referendum set for September 25... until it examines the complaints it has received over this plebiscite being unconstitutional," it said in a statement.

The court took the decision after it "reviewed requests to stop the referendum", the statement said.

Court spokesman Ayas al-Samouk, told AFP: "We have received several complaints and this is why we decided to suspend the referendum."

A source in parliament said at least three lawmakers had filed complaints against the poll.

Neighbours Turkey and Iran, as well as the United States and United Nations, have pleaded for the autonomous Kurdish region of northern Iraq to settle its differences with Baghdad through negotiations rather than secession.

Iraqi Kurdish leader Massud Barzani has said a "yes" vote would not trigger an immediate declaration of independence but rather kick-start "serious discussions" with Baghdad.