PHNOM PENH, Cambodia -- A Cambodian court on Friday ordered the arrest of opposition leader Sam Rainsy, who is locked in a bitter political fight with his archrival, the country's prime minister.

However, it is not clear if Rainsy will actually be arrested since he has parliamentary immunity due to his status as a lawmaker. He is currently on a trip to Japan and South Korea and is scheduled to return Nov. 16.

Rainsy was ordered arrested in connection with a defamation and incitement case brought by Foreign Minister Hor Namhong in 2008. In a speech, Rainsy had accused Namhong of colluding with the Khmer Rouge while he was a prisoner of the radical group.

The Phnom Penh municipal court convicted Rainsy and sentenced him to two years in jail. Rainsy appealed but lost in 2013. The conviction was never enforced and he continued to live freely in Cambodia, serving as the leader of his party in Parliament. According to Friday's arrest warrant, Namhong's lawyer, Kar Savuth, requested that the verdict be enforced.

In issuing the warrant, the court ordered "all public forces to search for and arrest" Rainsy.

The timing of the arrest warrant is certain to raise questions about a political motivation given that Rainsy has been engaged in a war of words with Prime Minister Hun Sen. On Thursday, Hun Sen called Rainsy the "son of a traitor" after the opposition leader said in Tokyo that Myanmar opposition leader Aung San Suu Kyi's electoral victory foreshadowed the downfall of Hun Sen.

"I cannot keep calm because of this insult by the son of a traitor," Hun Sen wrote on his Facebook page.

The Cambodia Daily newspaper quoted an opposition lawmaker, Eng Chhay Eang, as saying the arrest warrant was an attempt to keep Rainsy in exile and leave the opposition party leaderless ahead of 2017 village elections and 2018 national elections.

He questioned why the verdict was not enforced when Rainsy first returned to Cambodia in 2013 after nearly five years in self-imposed exile.

"It involves a case back in 2008, so why didn't they arrest him when Sam Rainsy was getting out of the airplane?" he said. "They want to show their power."

Hun Sen has been in office for almost three decades. While Cambodia is formally democratic, the government is notorious for intimidating opponents. Hun Sen has warned of civil war if the opposition wins the next election, suggesting that his followers would not accept such a result.

Relations between the government and the opposition deteriorated earlier this year after the opposition tried to exploit a volatile issue by accusing neighbouring Vietnam, with which Hun Sen's government maintains good relations, of land encroachment.

The anti-Vietnamese position proved politically popular, and the government reacted by stepping up intimidation of the opposition party in the courts, which are seen as being under its influence.