Thousands of Cambodians dressed in black and white gathered Monday ahead of the cremation of revered former king Norodom Sihanouk, who steered the war-ravaged kingdom through six turbulent decades.

The cremation is part of a week-long funeral for the mercurial ex-monarch, which started with a lavish procession through the streets of Phnom Penh on Friday and will see his ashes returned to the palace on Thursday.

Mourners jostled to get to the front of the queue early Monday to enter the cremation site to pay their last respects to the chameleon king, who was deft at moving with the political tides. Others sat and prayed on a street outside.

Sihanouk, who towered over six tumultuous decades in his nation's history, died of a heart attack in Beijing in October, aged 89.

Thousands of people had queued up at the crematorium over the weekend for a glimpse of the gilded casket containing the embalmed body of the beloved former monarch, while fireworks have illuminated the sky each evening.

Mourners have also grouped outside the royal palace to hold prayers, light incense and place lotus flowers in front of portraits of Sihanouk.

After religious ceremonies led by Buddhist monks, his widow Monique and son King Norodom Sihamoni are to symbolically light the pyre in a city park near the palace.

Exact details of the cremation were being kept under close wraps but the palace said that "modern techniques" would be used.

Foreign dignitaries including French Prime Minister Jean-Marc Ayrault, Japan's Prince Akishino and several Southeast Asian leaders are due to attend the ceremony, which starts at 0900 GMT, along with Cambodian royals and government officials.

More than 400 recently pardoned prisoners will also attend the event, which will be marked by a 101-gun salute.

"It's the last day for us all to pay homage to the great hero king and to send him to heaven," said Sihanouk's long-time personal assistant Prince Sisowath Thomico.

"It is the day for the whole nation to say goodbye to his majesty. He is the hero of Cambodia," Thomico told AFP, but added that only officials and guests would be allowed inside the actual cremation site in Phnom Penh.

Crowds of mourners thronged the capital on Friday when his body was paraded through the city in a gilded casket to a specially built crematorium in a Phnom Penh park, after lying in state at the palace for three months.

After the cremation, some of Sihanouk's ashes will be scattered where the Mekong, Tonle Sap, and Tonle Bassac rivers meet.

The remainder will be taken to the royal palace on Thursday where they will be kept in a royal urn in line with former king's wishes.

A father of 14 children over six marriages, Sihanouk abdicated in 2004 after steering Cambodia through six decades marked by independence from France, civil war, the murderous Khmer Rouge regime, his own exile and finally peace.

But even though the ever-changeable monarch had allied himself with the Maoist movement, Sihanouk -- a self-confessed "naughty boy" who loved to direct films, write poetry and compose songs -- remained hugely popular.

"He earned independence, peace, and prosperity for the country. Now he has gone, I'm worried that peace might vanish in the future," said Sum Seun, 60.

Observers say that while the royals remain highly revered by many elderly Cambodians, the monarchy appears to be growing less relevant in the eyes of the younger generation, and attendance at Friday's funeral procession appeared to fall well short of the one million people predicted by the government.

"I'm too busy to go to the funeral. It's important, but I don't have time," said a 25-year-old man who gave his name as Sna.