By Prak Chan Thul
PHNOM PENH (Reuters) - Opposition lawmakers boycotted the opening of Cambodia's parliament on Monday, threatening a constitutional crisis, after the authorities refused to hold an independent inquiry into alleged vote-rigging by the party of Prime Minister Hun Sen.
King Norodom Sihamoni issued a decree reappointing Hun Sen, giving the royal seal of approval to the results of July's general election, and the long-serving premier is expected to outline his new government's policies to parliament on Tuesday.
Security at the National Assembly and elsewhere in the capital, Phnom Penh, was tight, with many roads blocked off after opposition protests last week in which one man died.
"Our goal still stands. We are boycotting today's meeting because the truth has not been uncovered and there has been no breakthrough," Yim Sovann, a lawmaker for the opposition Cambodia National Rescue Party (CNRP), told Reuters.
"This meeting is a violation of the constitution."
The National Election Committee (NEC) says Hun Sen's Cambodian People's Party (CPP) won 68 seats in the July 28 election to the CNRP's 55. That was already a big setback for Hun Sen, but the CNRP claimed victory, saying it was cheated out of 2.3 million votes.
The opposition and some political analysts say a quorum of 120 lawmakers is needed to open parliament. Hun Sen has ignored that, saying the rules stipulate a new government can be formed if 63 of the 123 lawmakers vote in favour.
"The positive mood that was witnessed during the campaign period and the hope inspired by the election outcome, which signalled that Cambodia was on a sure path to a fully functioning democracy, are now fading," said Ou Virak, president of the Cambodian Center for Human Rights.
But he thought the opposition would continue to press for concessions. "They can also look for signs of division and breakdown within the ruling party as I think their ultimate goal at this stage is to see Hun Sen, not the CPP, out of power."
Hun Sen and CNRP leader Sam Rainsy held talks last week and agreed to look at how future elections are held plus possible reforms to national institutions. However, the premier has refused to accept any further investigation into the July poll.
A U.S. embassy statement issued after parliament opened called for "a transparent review of irregularities", to help address flaws in the electoral process.
It called on the two parties to follow up on a statement last week agreeing to further dialogue. "We believe that a functioning National Assembly requires the participation of both major political parties."
The European Union urged both sides to work to reform the electoral process. But the National Assembly, it said in a statement, "cannot serve its purpose without the participation of all elected political parties".
Independent analyst Chea Vannath said that while the CNRP had the right to demand an independent inquiry, the investigation could go ahead at some time in the future.
"The king has already issued a message and things can't go back ... The CNRP should start the hard work that will be needed over the next five years," she added.
King Sihamoni had turned down a request from the CNRP to delay the start of parliament, saying he was constitutionally required to preside over the opening within 60 days of the poll.
In his address to the house, the king said newly elected members of parliament had to put the national interest first.
"The Cambodian nation must stand united and show the highest national solidarity based on the implementation of the principles of democracy and rule of law that we have been practising since 1993," he said.
That year Cambodia held its first elections, under United Nations supervision, since before the ultra-maoist Khmer Rouge regime of the late 1970s and the civil war that followed.
Hun Sen, 61, has been in power for 28 years and has said he will rule Cambodia into his seventies.
He portrays himself as the man who saved Cambodia from the terror and chaos of the Khmer Rouge years. But his authoritarian rule, along with widespread corruption, alienated many young people who did not live through that era and who turned to the newly merged opposition CNRP in the election.
(Writing by Alan Raybould; Editing by Paul Tait and Ron Popeski)