BANQUE Nationale de Paris (BNP) will open an offshore banking office on the Malaysian island of Labuan, says a spokesman. France's second largest commercial bank received the authorisation from the Malaysian Government for a branch on the island, which has been designated for offshore banking purposes, said BNP spokesman Herve de Vaulx. BNP has had a representative office in Malaysia since 1975, but the Labuan operation will be its first branch in the country. Elsewhere in Asia, BNP this month opened a branch in Tianjin, China, after opening one in Ho Chi Minh City, Vietnam, last year. The bank also plans to open a bank in Bangkok and a representative office in Taiwan. It created the Banque Internationale de Paris et de Shanghai in July 1992. Meanwhile, Australia has given Singapore's United Overseas Bank (UOB) permission to operate a branch, according to a bank official. ''A focus of the branch will be to utilise its branch network in a number of countries to play an active role in financing trade and investments between Australia and the ASEAN region, in particular Singapore,'' said UOB assistant treasurer George Gear. The Australian Government decided last year to let foreign banks operate in Australia through branches rather than subsidiaries. ''The liberalisation of foreign bank entry . . . is directed at increasing competition in the banking sector,'' Mr Gear said. He said the bank would use its Australian branch to promote closer business relationships. between the Association of Southeast Asian Nations and corporations in Australia.