The Dalai Lama will meet 11 senior Buddhist monks on Wednesday morning before delivering a written statement that will "most probably" talk about his eventual succession as the spiritual head of Tibetan Buddhists, an official said.

Tibetan Buddhists believe that enlightened monks are reborn to continue their spiritual legacy. The 14th Dalai Lama will turn 90 on Sunday and has long been expected to use the occasion to share possible clues on where his successor, a boy or a girl, could be found following his death.

Beijing views the Dalai Lama, who fled Tibet in 1959 after a failed uprising against Chinese rule, as a separatist and says it will choose his successor. The Dalai Lama has said his successor will be born outside China and has urged his followers to reject anyone chosen by Beijing.

The northern Indian town of Dharamshala, where the Dalai Lama is based with thousands of other Tibetans, has already seen the arrival of the heads of various sects of Buddhism ahead of a Wednesday-Friday religious conference that precedes the birthday celebrations on the weekend.

"All the religious heads are here and they are going to talk to His Holiness, which may relate to reincarnation issues," said Tenzin Lekshay, spokesperson for the exiled government in Dharamshala, as mists and rains cloaked the Himalayan hills.

On the first day of the conference, more than 100 religious figures, including the senior monks, will issue a declaration of gratitude to the Dalai Lama and discuss the way ahead, he said.

The Dalai Lama will address them in Tibetan in a pre-recorded message, but is unlikely to refer to reincarnation in that message, Lekshay said.

The issue will "most probably" be covered in a written statement to be issued by the Dalai Lama late morning, he said.

Another official, speaking on condition of anonymity, said the written statement would refer to his reincarnation.