Cambodian lawyers filed a lawsuit to demand the dissolution of Cambodia's main opposition party after its leader, Kem Sokha, was charged with treason last month. Picture: AP Photo/Heng Sinith, File

Phnom Penh - Cambodian government lawyers filed a lawsuit on Friday to demand the dissolution of Cambodia's main opposition party after its leader was charged with treason last month.

The arrest of Kem Sokha on September 3 brought condemnation from Western countries, while his Cambodia National Rescue Party said it was a ploy by Prime Minister Hun Sen to win an election next year and keep his three-decade hold on power.

Lawyers for the government said the opposition had conspired with foreigners to topple the government, citing a 2013 video clip that shows Kem Sokha talking about a plan to take power with the help of Americans.