JOHANNESBURG (Reuters) - A South African peace conference of Nobel laureates has been postponed after the government's decision to deny a visa to Tibet's spiritual leader the Dalai Lama, organisers said on Tuesday.

Several Nobel peace prize winners had threatened to boycott the event over the visa ban, but the government said it was standing by its decision. Local media said the visa was refused after pressure from China, a big investor and trade partner.

The conference, due to take place on March 27, was organised by soccer authorities in South Africa, the host of the 2010 World Cup, and was expected to use soccer as a way of fighting xenophobia and racism ahead of the tournament.

"We have decided to postpone the peace conference until further notice," said Irvin Khoza, South Africa 2010 Organising Committee chairman. He said it would be postponed until all those invited could attend.

Government spokesman Thabo Masebe had said the Dalai Lama's presence was not in South Africa's best interest at the moment.

"We stand by our decision. Nothing is going to change. The Dalai Lama will not be invited to South Africa. We will not give him a visa between now and the World Cup," he said.

The decision to refuse the Dalai Lama a visa has come under severe criticism from opposition parties in a country which has prided itself as a model of democracy and human rights since the end of apartheid in 1994.

The Dalai Lama fled Tibet in 1959 and set up a Tibetan government-in-exile in India after a failed uprising against Chinese rule.

Rioting broke out last March in Tibet's main city of Lhasa after several days of peaceful protests by monks against Beijing's rule, killing 19 people and sparking a wave of violence across Tibetan areas. Exile groups say more than 200 people died in the crackdown.

The Dalai Lama was invited to participate in the conference by fellow Nobel laureates Archbishop Desmond Tutu, FW de Klerk and Nelson Mandela.

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