The coalition's Sephiri Motanyane beat Mosisili's Democratic Congress candidate with 71 votes to 49, when the house convened for the first time since May 26 elections in the tiny mountain kingdom enclaved in South Africa.

Wednesday's vote indicates the prime minister could not form a coalition to stay in power. His party won only 48 seats in the 120-seat parliament and could only get a single vote from a coalition partner.

Mosisili resigned last Wednesday while he tried to drum up support to be re-appointed. He remains in power until a new prime minister is elected.

This will be the first time an incumbent is unseated by the opposition in polls in Lesotho.

Main opposition parties the All Basotho Convention and the Lesotho Congress for Democracy, together with a few smaller parties, formed a coalition to oust him from power after 14 years, following the country's closest ever election.

The 1998 election that brought Mosisili to power sparked a violent reaction from the opposition, which in turn prompted military intervention from South Africa to restore order.

The new administration will be the first time the constitutional monarchy has been ruled by a coalition government.