KUALA LUMPUR (REUTERS) - Cambodia's self-exiled opposition veteran Sam Rainsy said on Sunday (Nov 10) he would help organise protests against authoritarian ruler Hun Sen to build on growing international pressure for change in his home country.

Rainsy told Reuters in Malaysia he thought Mr Hun Sen was being influenced by foreign measures against his government after house arrest restrictions were lifted on fellow opposition leader Kem Sokha, who was charged with treason two years ago.

"To maintain the pressure on Hun Sen, we will organise demonstrations all over the country and there is also a campaign on Facebook to encourage people to like and share what we post," Rainsy said in an interview.

Rainsy, 70, flew into Malaysia on Saturday and told supporters to "keep up the hope" after promising to return home to rally opponents of Mr Hun Sen, 67, a former Khmer Rouge commander who has ruled his South-east Asian country of 16 million people with an iron hand for 34 years.

A Cambodian foreign ministry spokesman said any appeal for demonstrations by Rainsy would be useless after he failed to make good on a promise to return to the country on Saturday.

"His supporters have lost their confidence and trust in him since things have never happened as he has repeatedly vowed," Mr Koy Kuong said, adding that no outside influences had affected the case of Kem Sokha.

Rainsy, who fled to exile in 2015, did not say how the opposition planned to organise demonstrations in a country where security forces have arrested 50 people accused of opposition links in recent weeks and crack down on any sign of dissent.

Rainsy acknowledged that even sharing anti-Hun Sen messages on social media can be risky for Cambodians.

Cambodia's government has said it will act against anybody threatening national security.

"We will encourage people not to be afraid," he said.

Rainsy would not say if, when or how he now planned to return to Cambodia, from where he fled a defamation conviction and other charges he says were politically motivated.

"In the near future, we will find ways and means to return to Cambodia. I cannot elaborate the plan in details but definitely we will return to our country," he said.

EU DECISION

Rainsy said it was clear that international pressure was having an effect on Cambodia with the European Union due to decide this week on whether to go through with a threat to remove valuable trade preferences over the opposition crackdown.

The opposition Cambodia National Rescue Party, founded by Kem Sokha and Sam Rainsy, was banned in 2017 ahead of elections last year that western countries dismissed as farcical.

"Internal pressure and external pressure will combine with the end result of making Hun Sen backtrack, of making Hun Sen withdraw all the repressive measures," Rainsy said.

Rainsy called for all charges to be dropped against Kem Sokha and for the party to be reinstated.

Rainsy was allowed into Malaysia after an earlier attempt to fly to Thailand from Paris was aborted when he was barred from boarding a Thai Airways plane.

"Geographically it is closer to Cambodia and it did increase this political, or moral, or psychological pressure on Hun Sen to release Kem Sokha and hopefully to take other measures to ease the political tension in Cambodia," he said.