ABEOKUTA, Nigeria -- Allegations of widespread electoral bungling and fraud -- including possible signing up of ghost voters -- grew Monday during a a 10-day voter registration campaign for Nigeria's first civilian-run elections since military rule ended.

Opposition parties charged the sign-up problems meant Africa's most populous nation risked failing a major test of its young democracy.

During the registration campaign, which ends this weekend, election overseers aim to register half of Nigeria's 120 million people for 2003 elections. Next year's vote will see the first democratically elected leader in nearly two decades -- President Olusegun Obasanjo -- contending for a second term.

The Alliance for Democracy, one of Nigeria's two largest opposition parties, complained Monday of numerous "irregularities, which can mar the entire exercise and defeat its very purpose."

Problems noted by its workers included registration stations that moved without notice, closed early or lacked forms -- thwarting would-be voters, the opposition party said.

Other problems reported by international election observers and others included stations that claimed to be signing up voters more quickly than appeared humanly possible -- while, in contrast, no registration at all was under way in some of the nation's hot spots.

Journalists reported possible fraud -- and The Associated Press watched a young male who appeared to be about 10 sign up and walk away with a card proclaiming him a registered voter.