A palace official said the plan to invite King Sihanouk to be present at the summit between prime minister Hun Sen and Prince Ranariddh might not be successful.
The official who asks to remain anonymous said the King has said before that all three major parties have to be present in any meeting.
CPP spokesman Khieu Kanharith said it's only a plan at this point.
The Sam Rainsy party said it doesn't mind and it's up to the King whether or not the opposition party should attend.