The main opposition Cambodia National Rescue Party (CNRP) will stage mass rallies in capital Phnom Penh and tourist city of Siem Reap on December 10 to celebrate the International Human Rights Day, a party spokesman said Thursday.

"We plan to mobilize 20,000 people in Phnom Penh and at least 10,000 participants in Siem Reap,"Yem Ponharith told Xinhua.

In Phnom Penh, participants will meet in front of the National Assembly to demand greater respect for human rights, he said, adding that in Siem Reap, they will gather at the Angkor Kyung Yu recreation ground, about 7 km away from the Angkor Wat Temple, a World Heritage site.

CNRP leader Sam Rainsy will join the rally in the capital in the morning and fly to Siem Reap in the afternoon.

Tourism Minister Thong Khon has urged the CNRP to avert violence when it stages mass rally in the tourist city in northwestern Siem Reap province.

Yem Ponharith said from Dec. 15 onwards, the CNRP will hold mass protests in Phnom Penh every Sunday in order to demand probe into the allegations of serious fraud and irregularities during the July election that handed victory to Prime Minister Hun Sen's ruling party.

"We will continue protests and boycott of parliament unless there is investigation into the poll," he said.

The July poll result showed that Prime Minister Hun Sen's party won the majority with 68 out of 123 parliamentary seats, and the CNRP got 55 seats, but it refused to accept the outcome.

Despite the opposition's boycott of parliament, the ruling party lawmakers voted on Sept. 24 for the establishment of a new government under the leadership of Prime Minister Hun Sen.