Cambodia has approved a law on how to choose a new monarch, a day after King Sihanouk's abdication announcement.
King Sihanouk's successor will be chosen by a nine-member council
The king's decision shocked Cambodia, not least because the constitution, rewritten in 1993, does not cover the issue of abdication.
The new law specifies that a nine-member Throne Council must meet within seven days to elect a successor if the king "dies, retires or abdicates".
Despite the move, efforts are under way to make the king change his mind.
His son and head of the National Assembly, Prince Ranariddh, is due to fly to Beijing on Saturday to try and dissuade his father from stepping down.
After a two-hour debate, lawmakers voted unanimously to set up the nine-member Throne Council, which is likely to include Prince Ranariddh, Prime Minister Hun Sen and
acting head of state Chea Sim.
"This is a historic day," Prince Ranariddh told reporters after
Laws for deciding succession still not agreed
Nine-member throne council decides between candidates
King thought to want Prince Sihamoni to succeed
Eldest son Ranariddh says he does not want the post
"I thank the lawmakers for passing this
The new law still has to be approved by the Senate on Monday, as well as being reviewed by a constitutional committee and signed into law by Chea Sim.
Initially there was some doubt over whether King Sihanouk could abdicate at all, since the current constitution only allows for a succession in the event of the monarch's death.
The new legislation indicates that Prime Minister Hun Sen's government appears ready to overlook this technicality.
But while he is helping to facilitate the process to choose a successor, Prince Ranariddh has made it clear that he wants to try and persuade his father to stay on, arguing that neither himself nor his half-brother Norodom Sihamoni wants to be king.
Prince Ranariddh will meet his father on Saturday in Beijing, where he has been receiving medical treatment.
Prince Sihamoni is the leading candidate to become the next monarch.
A classically trained dancer, he has worked in Paris for the United Nations cultural organisation, Unesco. More recently, he has been with his father in China.
In a letter read on state television late on Wednesday, the 81-year-old king asked that he be allowed to "retire" because of his fragile health, saying that doctors have detected a "new and serious ailment" in his stomach.
There is speculation that King Sihanouk has made the move to force the Cambodian authorities to hammer out the succession process.
Norodom Sihanouk's reign has been as turbulent as his country's history, interrupted by civil war and the Killing Fields of the communist Khmer Rouge when more than 1m of his subjects were killed by starvation or execution.
In recent years he has spent much of his time abroad running his own outspoken website, commenting on Cambodia's endless political power struggles.
King Sihanouk has said he will not return to Cambodia until a new monarch has been chosen.