Zambia on Friday awaited the first election results from what is expected to have been a close contest between President Edgar Lungu and his main rival, who accuses him of mismanaging the economy.

Lungu narrowly beat opponent Hakainde Hichilema in a presidential vote nearly 20 months ago to fill the vacancy created by the death of then president Michael Sata, and could be forced into a second-round rerun if he does not get an outright majority this time.

Although the final voting tally was not yet available, electoral officials reported a high turnout in Thursday's elections, where Zambians also voted for members of parliament and councillors.

The economy of Africa's second largest copper producer is under stress after weak commodity prices hit exports, and the government is trying to negotiate a support programme with the International Monetary Fund.

During the campaign, supporters of Lungu's governing Patriotic Front tussled with those of Hichilema's United Party for National Development, but there were no reports of violence on the day of the election.

If no candidate wins more than 50 percent, a second round between the two leading vote-getters must be held within 37 days.

Hichilema, a businessman and an economist by training, says he is more qualified than Lungu, a former lawyer, to steer the economy out of its slump.

But Lungu, who has been in office for just a year and a half, says he needs more time to diversify the economy from copper.

The Electoral Commission of Zambia has said it plans to have all of the election results announced by late Saturday or early Sunday.