In the capital Lilongwe, businesses in the city centre remained closed as nearly 3,000 marchers gathered in the streets.

In Blantyre, the financial capital, similar numbers turned out as army vehicles patrolled.

The aid-dependant southern African nation has seen two months of protests by demonstrators who dismiss the election as fraudulent and demand the resignation of election commission chairwoman Jane Ansah.

"We are continuing with our vigil to make our demands," protest organiser Billy Mayaya told AFP.

"If she does not resign... the tension will continue to escalate."

Among the protestors were opposition leader Lazarus Chakwera of the Malawi Congress Party (MCP), who alleges he was robbed of victory, and former vice president Saulos Chilima of the United Transformation Movement (UTM) party.

Opposition leaders claim correction fluid was used on some results sheets.

Mutharika, leader of the ruling DPP party, narrowly defeated Chakwera in the May 21 vote.