Lawmakers in the Democratic Republic of Congo passed a new electoral law Wednesday as they prepare for presidential and parliamentary elections later this year.

The new law, a revision of the 2006 electoral code, calls for the votes to be held in a single round. President Joseph Kabila says it is a cost-saving measure for a vast country whose crumbling infrastructure makes even delivering ballots a difficult task.

But opposition parties have criticized the change, which was first approved as a constitutional amendment earlier this year. More than 100 lawmakers boycotted the vote in January.

The move is seen to benefit Mr. Kabila in his expected run for a second term. He will likely face a number of candidates from opposition parties, splitting the opposition vote.

Meanwhile, voter registration is set to finish by the end of the month, but opposition parties are saying they need more time. Party officials say delays and logistical problems have meant thousands of people have not yet been able to register. One official says some registration centers have yet to enroll even one voter.

Seven opposition parties are calling for a 30-day extension, saying an incomplete voter list could undermine the credibility of the polls. The independent electoral commission says it is looking into the issue.

Extending voter registration could lead the elections, scheduled for November 28, to be pushed back as well.

These are just the second national polls since the civil war ended in 2003.

The DRC is a vast country of some 60 million people, fractured by years of war, unrest, and ethnic strife.

Analysts say that under a one-round election system, a presidential candidate could win with as little as 20 percent of the vote.

President Kabila was elected in 2006, defeating opponent Jean-Pierre Bemba in a runoff.