Cambodia's charismatic opposition leader Sam Rainsy arrived in his home country on Friday morning after spending nearly four years abroad in self-imposed exile to avoid an 11-year prison sentence on charges of disinformation and destruction of public property.

At the Phnom Penh International Airport, Sam Rainsy, president of the Cambodia National Rescue Party (CNRP), was greeted by tens of thousands of supporters.

His return came after King Norodom Sihamoni granted him a royal pardon at the request of Prime Minister Hun Sen last Friday.

Hun Sen said his request to the king was based on the spirits of national unification and reconciliation, and to enable the fifth National Assembly elections on July 28 to be held in accordance with democratic, multi-party principles whereby all relevant parties can participate.

Tep Nytha, secretary general of the National Election Committee (NEC), said that Sam Rainsy was ineligible to vote or run as a parliamentary candidate for the upcoming polls because the NEC deleted his name from the voter registry since November on the grounds that he was a convicted criminal at that time.

"With the royal pardon, Sam Rainsy is free to campaign for his party in the polls, but he can neither vote nor stand as a candidate," he told reporters at a meeting at the NEC headquarters in Phnom Penh on Thursday.

According to the CNRP, Sam Rainsy will hold an election campaign in Phnom Penh City soon after his arrival and will set off the following day for a week-long tour of 15 provinces.