Nigeria said on Monday it had withdrawn its bid to host the 2010 World Cup and would back the South African campaign instead.
"In the spirit of African brotherhood, and Nigeria, especially with her cordial relationship with South Africa, the federal government has withdrawn from the bid of the 2010 World Cup fiesta and lends its full support to South Africa," Sports Minister Musa Mohammed told a news conference.
It was not clear if Nigeria's decision had yet been communicated to world soccer's governing body FIFA, who were expecting the bid to be presented along with five others in Zurich on Tuesday.
The five -- South Africa, Morocco, Egypt, Tunisia and Libya and Nigeria -- all announced their bids last year.
South Africa, the clear favourites since narrowly losing the 2006 World Cup hosting to Germany, were delighted with the Nigerian decision.
"It's great news for South Africa and our bid," South Africa's bid chief Danny Jordaan said from Zurich on Monday.
"More important than Nigeria backing out is the fact that they have given us their support because they are extremely influential in West Africa and will be able to consolidate a large amount of support behind the South African bid."
In 2000, Nigeria also withdrew its bid to host the 2006 World Cup and threw its weight behind the South African campaign.
FIFA has said Africa will host soccer's showpiece event for the first time in 2010 as part of a new policy of rotation of the tournament between continents.
Mohammed said oil-producing Nigeria was overburdened by other commitments, namely the hosting of the All Africa Games from October 4 to 18 and the Commonwealth Heads of Governments Meeting in December.
"The enormous expenditure on government are high and, therefore, make the World Cup bid undesirable," he said.
"Consequently, all activities relating to the bidding exercise is hereby stopped and the World Cup bid management committee is hereby dissolved."
Nigerian bid leader Segun Odegbami said he was not surprised at the government's decision.
"We saw it coming because we all saw the lack of enthusiasm from government ... not wanting to give approval or a guarantee," he told Reuters in Lagos.
"We have done the job government gave the team now the same government has withdrawn the bid. Who am I to oppose?"
Despite being sub-Saharan Africa's biggest economy after South Africa, Nigeria has some of the poorest infrastructure on the continent and not even many of its own citizens gave its bid much of a chance.
Nigeria had originally hoped to bid jointly with West African neighbours, Benin, Ghana, Cameroon and Togo, but FIFA rejected the move.
Mohammed said the FIFA rejection as well as criticism from the Nigerian media and soccer experts also played a part in the decision to withdraw the bid.