PHNOM PENH (Reuters) - The ruling Cambodian People’s Party (CPP) of Hun Sen is poised to sweep a Senate election at the weekend, helping to consolidate the prime minister’s rule of more than 30 years amid a crackdown on the opposition.

Slideshow ( 4 images )

Sunday’s election for 58 members of the 62-strong Senate will see 123 members of parliament and 11,572 commune councilors vote at 33 polling stations across Cambodia. Two Senate members each are appointed by the king and the National Assembly.

But rights groups and opposition politicians say the Senate vote is a farce that shows Hun Sen, who faces a national election in July, is not committed to multi-party democracy.

Almost half of the commune councilors have been stripped of their right to vote in Sunday’s election after their opposition Cambodia National Rescue Party (CNRP) was dissolved by a court last November at the request of Hun Sen’s government.

“It’s the first time the Senate election will be held without the main opposition, without competition,” said Koul Panha of the Committee for Free and Fair Elections in Cambodia, an election watchdog.

About 5,007 CNRP commune councillors, or 44 percent of the 11,572 eligible to vote, had been stripped of their voting rights, he added.

“It’s neither democratic nor free and fair.”

Only three small political parties are contesting the vote, apart from the CPP.

“I expect that we will win by a lot,” said Sok Eysan, a CPP spokesman in the running for Sunday’s election. “It is 100 percent sure that I will be elected.”

The ruling CPP was the only party to hold rallies during the 14-day campaign period leading up to Sunday’s vote, the National Election Committee said.

The Senate, whose members have six-year terms, is seen as a rubber stamp institution, but the president has constitutional power as the head of state to sign bills into law when the king is abroad.

Dissolution of the CNRP was followed by the arrest of its leader Kem Sokha last year for allegedly plotting to overthrow the government with U.S. help, an accusation both the United States and Kem Sokha have rejected.

The CNRP ban effectively removes any major obstacles to Hun Sen’s re-election in July.

Mu Sochua, the deputy president of the CNRP, called Sunday’s vote a “sham”, saying it would further widen Cambodia’s political divide.

“It is a sham election for the sole interest of the CPP to maintain and control absolute power,” Mu Sochua, who lives abroad in self-imposed exile, told Reuters.