BEIJING, May 7 (AFP) - China on Wednesday denied it had decided to end use of Tibetan as the main language in Tibet's primary schools.

"These are rumours," said Han Zihong, director of the Primary Education Department at Tibet's Education Commission, denying reports of any policy change.

He said the use of the indigenous language in early education was a part of the basic legal structure that defines Tibet as an autonomous region, rather than a regular Chinese province.

The London-based Tibet Information Network (TIN) said Tuesday that Chinese authorities had decided to reverse 1987 education regulations supporting use of Tibetan.

It quoted Tenzin, a deputy secretary of the Communist Party in Tibet, as saying last month that allowing children to be taught only in Tibetan was "impractical" and "not in conformity with the reality of Tibet."

But Han said: "The reality is that in primary schools, we use Tibetan for all courses."

Among more than 4,000 elementary schools in Tibet, there are only one or two who teach only in Chinese, the official told AFP by telephone.

Children of country herders begin to study Chinese in their fourth year of school, he said, whereas city children start in their first or second year.

The issue is sensitive because Beijing has been accused of cultural genocide in Tibet, where large numbers of ethnic Chinese settlers already dominate major cities.

Chinese troops seized control of the Himalayan region in 1951, but it was not declared an autonomous ethnic region until 1965.

According to TIN, the 1987 policy which also called for the establishment Tibetan-language junior secondary schools and university courses had never been implemented.

Tibetan students currently switch to Chinese-only instruction at the age of nine, it said, adding that the shift had led to widespread underachievement by Tibetans in secondary and higher education.