King Sihanouk's decision to abdicate has been complicated by the fact that there were no clear rules on choosing his successor.
Prince Sihamoni, a trained dancer, may become the next king
Under the 1993 constitution Cambodia's is not a strictly hereditary monarchy.
What the constitution does stipulate is that in the event of the king's death, the Royal Throne Council must choose a successor within seven days.
There were no provisions for the retirement or abdication of the king.
However, following King Sihanouk's announcement, the country's National Assembly and Senate rushed into force legislation to allow the Throne Council to appoint a new monarch anyway, and stipulate exactly how this should be done.
The Throne Council is made up of the prime minister, the two heads and four deputies of the Senate and the National Assembly, and two top Buddhist monks.
The Prime Minister, Hun Sen, is believed to wield considerable influence over the rest of the Council, and it is thought that he is likely to be able to push his choice through.
But it is not yet clear who is in the running.
The constitution stipulates that the next king has to be a member of the Royal family, at least 30 years old, and a descendant of one of three former kings.
That leaves dozens of potential candidates, but most of the speculation has centred around Prince Norodom Sihamoni, a 51-year-old trained dancer and former ambassador to the UN cultural organisation, Unesco, in Paris.
PM Hun Sen (right) and Prince Ranariddh (left) will help decide
He is the only surviving son of the union between King Sihanouk and his current wife, Monique. Sihamoni's name is derived from the first syllables of his parents' names.
Prince Sihamoni is also rumoured to be the favoured choice of both Prince Ranariddh - his half-brother and the leader of the National Assembly - and the king himself.
However, Prince Sihamoni has shown little interest in Cambodian politics to date. He was educated in Prague and North Korea, and has been based in Paris since the 1970s.
But having a relative unknown on the throne may suit Hun Sen, who has dominated Cambodian politics for the last two decades.
Cambodia's king does not rule the country in any substantive sense, but he can wield considerable influence. King Sihanouk is viewed by the public as the country's unifying symbol and patriarch.
Prince Ranariddh, son of King Sihanouk and a former wife, has said he does not want to succeed his father.
Hun Sen may not want him to either, since the two men have a long history of rivalry.
The most serious was in 1997, when Hun Sen ousted the prince from their ruling partnership and forced him to leave the country.