Massive crowds of weeping Thais and saluting soldiers lined the streets yesterday as late King Bhumibol Adulyadej was borne through Bangkok, a day after his death left an apprehensive country facing an uncertain future.

Bhumibol, the world's longest-reigning monarch, passed away at 88 on Thursday after years of ill health, ending seven decades as a stabilising figure in a nation of deep political divisions.

The phenomenal reverence towards him in Thailand was on clear display as mourners sat for hours in Bangkok's urban heat awaiting the passage of his motorcade, in scenes reminiscent of religious devotees.

Pensive-looking men and women dressed in black were jammed cheek by jowl along roadsides in the capital on the short route from the hospital where Bhumibol died to his royal palace.

Some fainted and were carried away on stretchers, while others shouted "King of the people!" as the convoy of several vans bearing his body and the royal family slowly wheeled through hushed streets.

The king ruled 70 years and was the only monarch most Thais knew.

"We no longer have him," wept Phongsri Chompoonuch, 77, as she clutched the late monarch's portrait.

"I don't know whether I can accept that. I fear, because I don't know what will come next."

MOURNING BEGINS

At the palace, the crown prince was to preside over the bathing of the king's body, a traditional Buddhist funeral rite and the start of official mourning that will include at least 100 days of chanting by monks and months more of palace rituals.

Crown Prince Maha Vajiralongkorn, 64, is the king's named successor but has made a surprise request to delay formally assuming the throne, according to Thailand's junta leader, who appealed for citizens to "not cause chaos".

Bhumibol was seen as a pillar of stability during his politically turbulent reign, and uncertainty for the future rests largely on doubts over whether his son can exert the same calming moral authority.

The crown prince spends much of his time overseas and does not command the reverence at home that his father did.

There was no indication of a threat to the crown prince's eventual succession, however, and analysts said the pause could merely be out of respect for the deeply revered king.

Strict lese majeste laws muffle detailed discussion of the sensitive succession issue.

The military government of Prime Minister Prayuth Chan-ocha said civil servants would observe mourning for a year. He also urged Thais to refrain from "festivities" for 30 days. Flags would fly at half-mast at all government buildings and schools for 30 days, he said.

A royal cremation is expected to take months to prepare. When the king's sister died in 2008, a 100-day mourning period was declared. She was cremated 10 months after her death, reports Reuters.

The heir's coronation will not take place until the mourning period is over.