Nairobi/Accra  - Opposition candidate John Atta Mills has won Ghana's run-off presidential election, Joy FM radio station said Monday after collating results from polling stations.

While the Ghana Electoral Commission is yet to announce official results, Joy FM said Atta Mills, of the National Democratic Congress (NDC), has 50.6 per cent of the vote with 222 of 230 constituencies counted.

Nana Akufo-Addo of the ruling New Patriotic Party (NPP) has 49.4 per cent, Joy FM said.

The electoral commission has said it will announce results by Tuesday afternoon at the latest.

If Joy FM's results are accurate, Atta Mills will lead the West African nation into the oil era.

Ghana's National Petroleum Corporation expects 120,000 barrels per day to come onstream in 2010, with that figure rising to 250,000 barrels a day within two years.

Ghana is the second-largest cocoa grower in the world and Africa's second-biggest gold producer, yet there is still widespread poverty among ordinary Ghanaians.

Atta Mills has promised to address this poverty and battle high food and fuel prices.

While Sunday's election passed off peacefully, the two parties accused each other of attempting to rig the vote.

The NDC said its officials were intimidated and harassed. The NPP countered with claims that its polling agents were harassed by the NDC. There were also reports of attempted ballot box theft.

US envoy to Africa Jendayi Frazer called on both parties not to raise tensions by spreading rumours.

"Some of the statements by the political parties officials have been irresponsible and there are a number of rumours that have been going on that are being repeated by some of the radio stations that are associated with the parties," the BBC reported her as saying.

The election is seen as key to African democracy, which sorely needs a boost after electoral chaos in Kenya and Zimbabwe and coups in Mauritania and Guinea this year.

Foreign election monitoring teams were in place to observe the election. The EU's election monitoring team, which hailed the first round as a a credit to democracy, is due to deliver its verdict on the second round on Tuesday.

Atta Mills will replace John Kufuor, who must step down in January after serving two terms.

This is Atta Mills' third attempt at the presidency. He lost to Kufuor in a run-off in 2000 that saw the NPP grab power from the NDC and then in the first round in 2004. (dpa)