Cambodia's two main opposition parties have joined forces to challenge Prime Minister Hun Sen's 27-year grip on power at a general election next July, a spokesman for the new group said Wednesday.
The Cambodia National Rescue Party, formed by the Sam Rainsy Party and the Human Rights Party, received official approval from the interior ministry on Tuesday, said spokesman Pol Ham.
It will be headed by opposition leader Sam Rainsy, who is seen as Hun Sen's main rival but who lives in France to avoid prison for a string of convictions that critics contend are politically motivated.
"We hope that if Sam Rainsy can return we can win the election... or at least make it a closer race," Pol said, adding that many grassroots party members supported the move to team up.
For now, both parties will remain separate so that their elected officials can keep their seats until the next polls, Pol said.
At the last parliamentary election in 2008, Hun Sen's ruling Cambodian People's Party won 90 of the 123 seats in the National Assembly. The Sam Rainsy Party took 26 seats and the Human Rights Party just three.
Hun Sen, 61, has ruled the country since 1985 and has vowed to stay in power until he is 90. His government is regularly accused of suppressing political freedoms and mistreatment of rights campaigners.
Speaking to supporters via videolink on Tuesday, Sam Rainsy, 63, vowed to return to Cambodia by December. But the government insists he will have to serve time in jail if he does.
"We have never banned him from coming back -- it's his right. But the court already issued the verdicts and if he returns he surely can't avoid the legal process," government spokesman Keo Remy told AFP.
Sam Rainsy faces a total of 11 years in prison. He was sentenced to 10 years in absentia in 2010 for publishing a false map of the border with neighbouring Vietnam, though the punishment was later reduced to seven years.
He was also handed a two-year sentence for inciting racial discrimination and uprooting border markings with Vietnam in a 2009 incident.
Last year, he was given another two-year jail term for accusing the foreign minister of being a member of the brutal Khmer Rouge regime in the late 1970s.
