Governor Apirak Kosayodhin presided over the morning opening ceremony, which included a religious service dedicated to all deities, to Phra Siam Thevathirat - guardian of the Kingdom - and to Thailand's ancestral kings.

A procession escorted the relic to a temporary shrine in Sanam Luang.

Thailand's first propagation of the Tripitaka Buddhist canon was launched to run non-stop until Thursday with the laity attending readings of the scriptures by monks so as to better understand and apply their precepts.

Preecha Kanthiya, director-general of the Culture Ministry's Religious Affairs Department, said the department was sponsoring this with Mahachulalongkorn Buddhist University, Mahamakut Buddhist University and the Bangkok Metropolitan Administration.

Monks in groups of 30 will take turns to read out the scriptures, starting again when they have finished all 84,000 chapters of the 45 books, he said.

A Bt10-million Visakha Punnami exhibition organised by the Tourism Authority of Thailand (TAT) will focus on the Buddha's teachings and life by means of multimedia presentations, including video, installations and media art.

The exhibition covers 1,000 square metres divided into nine rooms, each with a theme, such as the Lord's teachings, the circle of suffering in life, self-awareness and the life of the Buddha.

TAT deputy governor Santichai Euachongprasit said that after Visakha Puja Day, the exhibition might be installed in the Buddha Monthol compound in Nakhon Pathom.