Gyanendra, whose reign is opposed by fiercely republican Maoists who joined the government earlier this year, plans to throw open his pink palace in Kathmandu for well-wishers to greet him Saturday and stage a reception Sunday.

"As an individual he's entitled to celebrate his birthday but as the king he has no rights to hold a public felicitation," Ganesh Man Pun, president of the Young Communist League, told AFP.

The student and youth groups will stage rallies Friday and Saturday to try and prevent the birthday celebrations, student leaders announced.

"Student and youth leaders... have decided to appeal to all to foil the king's birthday celebrations," Gokul Gharti, general secretary of the All Nepal National Free Students Union said.

On Thursday, ambassadors from the United States, India, the European Union and elsewhere snubbed the king by announcing they would not attend his party.

The monarchy's fate is set to be decided after crucial elections in November to elect a body that will rewrite the constitution.

Gyanendra and his 238-year-old Shah dynasty came under grave threat after the Maoists and mainstream political parties made peace and formed a government earlier this year.

The king has already been stripped of most of his powers including his job as head of the armed forces.

Gyanendra came to the throne after the 2001 massacre of most of the royal family by a drink-and-drug-fuelled crown prince who later killed himself.