ABIDJAN (Reuters) - Ivory Coast's main opposition party demanded a fixed schedule for staging the presidential election on Sunday, the latest in a string of missed target dates for a poll that is now over four years late.

President Laurent Gbagbo was due to hold an election in 2005 but has cited a variety of technical problems in going ahead with the poll, most recently plagued by confusion over whether around 1 million residents are eligible to vote.

Analysts say the delays have prolonged a political deadlock dating back to the 2003 civil war that is stopping vital reforms to the world's largest cocoa industry and unnerving potential investors in West Africa's former economic powerhouse.

"Since October 2005, our country has been governed by a president without a mandate," Alphonse Djedje Mady, general secretary of the Democratic Party of Ivory Coast (PDCI) told supporters at a meeting in Abidjan.

Mady called on other parties to join it in demanding that the Ivorian electoral commission rapidly set a new election target date and ensure it was finally met.

PDCI candidate and former president Henri Konan Bedie is tipped as Gbagbo's nearest rival, with former prime minister Alassane Ouattara closely behind him.

No new date has been set for the election after it was acknowledged this month that the poll would not go ahead as planned. Some observers predict that it could take months to resolve the inevitable disputes over voter eligibility.