Hun Sen took office after parliament re-elected him as the prime minister amid a boycott by the opposition party, Xinhua reported.
The premier, along with his newly approved cabinet members, took oath at the Royal Palace under the auspices of King Norodom Sihamoni and Buddhist monks Tep Vong and Bour Kry.
Parliament, consisting of the ruling party's 68 lawmakers, Tuesday voted for Hun Sen as the prime minister of a new government even though the opposition boycotted the session since it refused to accept the results of the July 28 election.
Under the country's constitution, a new government can be formed by a 50 percent plus one majority, or 63 lawmakers, in the parliament.
Hun Sen said the new parliament and government were formed in accordance with the constitution despite a boycott by the opposition's 55 elected lawmakers.
"We are all here, not the hostage of any group; we complete our duties in accordance with the constitution of Cambodia," the premier said during the parliamentary session in response to the comments by the opposition that the new parliament was held in violation of the constitution.
According to an official schedule, the first cabinet meeting will be held Wednesday at the Peace Palace.
Although Hun Sen's ruling party had successfully formed a new parliament and government, political analysts said the opposition boycott could affect the country's standing in the international community because the legitimacy of the new government could be questioned.
"Without the opposition's participation, the legitimacy of the new government would be questioned and its role and image on the international stage could be downgraded," Chheang Vannarith, senior researcher of the Cambodian Institute for Cooperation and Peace, told Xinhua.
He warned that the Cambodian economy would face huge challenges if there was no domestic political stability and national unity.
"In a political situation like this, both existing and potential investors would be reluctant or more cautious in investing in Cambodia," said Vannarith, who is also a lecturer at the Leeds University in Britain.
"If there is no peace and political stability, there is no development," he added.
Sok Touch, deputy chief of the Royal Academy of Cambodia's International Relations Institute, agreed that the opposition boycott would have an adverse effect on the country's foreign standing.
The US, Japan, Australia and the European Commission have urged the Cambodian government to transparently review the alleged irregularities in the July 28 national elections.
"If these countries do not support the new parliament, Cambodia will face an economic crisis because those countries are (the) main importers of Cambodian products, especially garments," he said.
"Moreover, investors and tourists from Western countries may hesitate to come to Cambodia."
However, Phay Siphan, spokesman for the council of ministers, defended the legitimacy of the new parliament and government.
"According to the constitution, a new government will be formed by a 50 percent plus one majority, or 63 lawmakers, in the new parliament," he told Xinhua Monday.
"And the CPP (Cambodian People's Party) has enough lawmakers to form a new government despite the opposition boycott," he said adding that the boycott by the opposition would not cause a crisis or political instability in Cambodia.
--IANS (Posted on 24-09-2013)