CONAKRY: Rival gangs fought with knives and truncheons in Guinea's crumbling seaside capital on Friday as ethnic tension worsened before an election in the unstable West African nation, witnesses said.

Security forces in full anti-riot gear piled into the backs of pick-up trucks and deployed across Conakry to separate the fighters as President Alpha Conde's government appealed for calm.

"It has become very bad. People set fire to a car right in front of me. I've seen four people injured in the fighting," said Souleymane Bah, a resident of Bambeto, one of several areas where clashes were reported.

"We've locked ourselves inside a bank. I can see people fighting outside," resident Abdoulaye Sylla, told Reuters by telephone from Conakry's Dixxin neighbourhood.

Residents in other areas fled in panic as the gangs from rival ethnic groups roamed the streets, according to witnesses.

The long-delayed legislative vote, tentatively set for May, is needed to complete a transition to civilian rule after a 2008 military coup, and could open the door to hundreds of millions of dollars in European aid.

Politics in Guinea are mainly drawn along ethnic lines with the opposition coalition broadly supported by members of the Peul ethnicity - the country's biggest ethnic group - and the government supported by the Malinke.

The fighting on Friday follows two days of anti-government protests that have sharpened those divisions.

Conde won a 2010 presidential election promising to unite Guinea in the same way Nelson Mandela did after apartheid in South Africa, but many of his compatriots say he has failed.

The opposition called last month for protests against preparations for the parliamentary election, saying the government was seeking to rig the vote in advance.

Two days of violent demonstrations followed in which one civilian was killed and scores of protesters and police were injured.

A government spokesman said on Friday that opposition leaders should call on their supporters to halt the fighting.

"We are going to make a declaration calling for calm. But the opposition leaders need to do the same thing," said government spokesman Damantang Albert Camara.

Opposition leader and former premier Sidya Toure said Conde's government had failed in its promise to reconcile Guinea's longstanding political and ethnic divisions.

"The situation has clearly degenerated into inter-ethnic violence between the Peuls and Malinkes. We've already called for calm, but what can you tell someone who is being attacked with a club?" he said.

Conde has promised prosperity for the former French colony's 10 million people, which is the world's top supplier of bauxite, the raw material in aluminium.

Guinea's economy produces only about $1.50 per person per day despite a wealth of natural resources, including the world's largest untapped iron ore deposit.