He returned from exile for the election on July 26th, but along with Mr Rainsy, who now runs his own party, claims that Mr Hun Sen's Cambodian People's Party won by a narrow margin only because of fraud and intimidation.
The Taliban have threatened to kill Mr. Musharraf, who returned last month after more than four years in self-imposed exile to run in the upcoming parliamentary election.
Former President Didier Ratsiraka, 76, who went into exile for several years after losing a disputed election to Mr Ravalomanana in 2002, is also on the list of candidates.