Cambodian's main opposition party is calling for electoral reform ahead of general elections in July, saying members of the national electoral committee are biased in favor of powerful Prime Minister Hun Sen.

Several thousand supporters of the Cambodia National Rescue Party staged a peaceful rally Wednesday in the capital, Phnom Penh.

They also called for a review of voter registration lists, saying as many as 1 million people are missing.

The National Election Committee says the lists are fine and its nine members are independent and do not need to be changed.

The committee's members were named by the interior ministry and approved last year by Parliament, which the ruling party dominates.

Hun Sen has ruled Cambodia for decades. Most believe his party will sweep the July legislative vote.