Police were investigating a suspect envelope containing white powder found in a Tibetan centre in Belgium on Monday, just days ahead of a visit by the Dalai Lama, officials at the centre told AFP.

"An envelope with white powder has been discovered. Tests are being carried out," said an official at the Yeuntenling Buddhist centre at Huy, some 80 kilometres (50 miles) from Brussels.

"The centre does not wish to make further comment," the official added after confirming that police were running tests on the suspect powder.

The exiled Tibetan spiritual leader, 76, Thursday addresses a gathering of followers at the centre, the biggest in Belgium, which itself plays host to Europe's second largest Tibetan community.

He will consecrate a new prayer hall and give a talk after holding a press conference.

In India, the Tibetan government in exile alleged this weekend that Chinese agencies are secretly collecting samples of the Dalai Lama's blood, urine and hair and are stepping up efforts to harm him.

"It is also learnt that they are exploring the possibility of harming him by using ultra-modern and highly sophisticated drugs and poisonous chemicals," said Dongchung Ngodup, minister of security in the cabinet.

"We have our own intelligence network in Tibet and we received these reports from our sources there," he told AFP.

The Dalai Lama is currently in Austria after last week meeting British Prime Minister David Cameron in what Beijing said was an "affront to the Chinese people".

The pair held a private meeting during the Dalai Lama's visit to London to receive the 1.1-million pounds ($1.8-million, 1.4-million-euro) Templeton Prize for spiritual leadership.