Congo's electoral commission has said Sunday's presidential vote will not take place and is calling for a postponement, opposition official Jacquemin Shabani told dpa.

‘The elections will not take place, this is what the president (of the electoral commission) told us. He is asking for a postponement,’ said Shabani, an official from opposition candidate Felix Tshisekedi's party.

The election has already been delayed for two years by President Joseph Kabila, in power for 17 years.

Ruling-party candidate and Kabila-protege Emmanuel Ramazani Shadary is pitted against two main opposition candidates, Tshisekedi and  Martin Fayulu.

But things have been heating up ahead of the vote, with at least 10 people killed in clashes with security forces and ruling party supporters at political rallies across the country, according to the Congolese Association for Access to Justice (ACAJ).

Last week, a huge fire - believed to have been set deliberately - destroyed 8,000 voting machines in a Kinshasa warehouse, leading some to question then if the polls would go ahead at all.

And on Wednesday the governor of the capital Kinshasa said campaigning was banned in the city due to threats of street violence.

The mineral-rich country with an impoverished population is already battling crises on multiple fronts; a hunger crisis in the central Kasai region, a deadly ebola outbreak in the east, and numerous militia groups.

Sunday's vote could possibly have seen the first peaceful transition of power in the troubled nation's history.