Bissau, Guinea Bissau - Malam Bacai Sanha has won a presidential run-off election in Guinea Bissau to replace assassinated president Joao Bernardo Vieira, election officials said Wednesday.

Sanha, the candidate for the ruling African Party for the Independence of Guinea and Cape Verde (PAIGC), polled 63 per cent of the vote, beating his opponent Kumba Yala.

Observers hope that the election will bring stability to a country blighted by instability since independence from Portugal in 1974.

Officials estimated turnout in Sunday's election at around 60 per cent of the 600,000 registered voters in the country.

Sanha was favourite to win after leading in late June's first round voting, which failed to produce a clear winner.

Both rounds of voting passed off peacefully, but political violence in the run-up to the election led international conflict resolution bodies to call on the loser not to turn to violence.

Vieira was killed by soldiers five months ago in an apparent revenge attack for the murder of the tiny West African nation's army chief.

Presidential candidate Baciro Dabo, a close ally of Vieira, and other political figures were murdered by government security forces in early June. They were accused of planning a coup.

Guinea-Bissau has been dubbed a "narco-state" for its role as a hub for drugs trafficked from South America to Europe.

No president in Guinea-Bissau has completed a five-year term since the early 1990s.

The election was also seen as important for the reputation of the region, where both Guinea and Mauritania have suffered coups and Niger's president is attempting to override the constitution and stay in power.

The United Nations ranks Guinea-Bissau as one of the most impoverished nations in the world, with a life expectancy of just 45 years. One in five children die before their fifth birthday.(dpa)