Botswana, Burkina Faso, Cameroon, Cape Verde Islands, Congo-Brazzaville, Ethiopia, Gabon, Libya, Malawi, Senegal, Tunisia, Uganda and Zambia complete the line-up of hopefuls.
The top two teams in the table square off in five groups, and in two others there are three sides battling to join already-qualified Algeria, Egypt and Ivory Coast.
A seeded September 16 draw in Cairo will create five home-and-away ties with the five winners representing the continent at the 2014 World Cup in Brazil.
In a 20-fixture schedule over five days, nine encounters count toward play-off places, starting with Group D leaders Ghana against second-place Zambia in Kumasi on Friday.
Ghana were the most successful African side at the last World Cup in South Africa three years ago, reaching the quarter-finals before losing a penalty shootout against Uruguay.
Midfielders Andre Ayew, Kevin-Prince Boateng and Michael Essien are available again, giving coach Kwesi Appiah an embarrassment of riches to select from.
Marseille star Ayew has had differences with national football association officials and Germany-born Boateng previously said he could not cope with the demands of AC Milan and Ghana.
Injury-prone Essien, who has returned to Chelsea from a loan spell at Real Madrid, said he wanted to prioritise his club career before returning to national duty.
A groin injury has ruled out goalkeeper Adam Kwarasey, but star striker Asamoah Gyan says he will be fit to face the ‘Chipolopolo’ (Copper Bullets) despite a heavily strapped right thigh.
“Qualifying will not be easy because Zambia also have a very good team,” warned Appiah, “but I am confident because the boys are really psyched up.”
Zambia have suffered a double blow in attack with experienced Collins Mbesuma (knee) and Jacob Mulenga (thigh) ruled out of a clash the visitors must win to stay in the hunt.
The shock 2012 Africa Cup of Nations winners beat Ghana 1-0 at home last year, but draws with lowly Lesotho and Sudan have left them a point behind the west Africans.
Nigeria have their destiny in their own hands with a home draw against Malawi in Calabar enough to move them within 180 minutes of a fifth World Cup appearance.
The Super Eagles boast a powerful squad with midfielder John Obi Mikel of Chelsea and striker Emmanuel Emenike of Fenerbahce available after missing a friendly win in South Africa.
Coach Stephen Keshi has branded Malawi “dangerous opponents” despite the central African ‘Flames’ losing to the Angolan Olympic squad and Botswana in warm-ups.
“It is great to have some stars for the first time since winning the Africa Cup last February and we must hit the ground running,” stressed 1994 World Cup captain Keshi.
Both teams are unbeaten in Group F with Nigeria winning two games and drawing three and Malawi winning one and drawing four in a pool including Namibia and Kenya.
South Africa, successful hosts of the last World Cup, are in danger of missing Brazil as they trail shock Group A pacesetters Ethiopia by two points.
Ethiopia, seeded fourth behind Bafana Bafana, Botswana and Central African Republic, qualified for the play-offs last June only to have three points docked for using an ineligible player.
But a team composed almost entirely of home-based stars can seal first place with a win over C.A.R., a fixture held in neutral Congo-Brazzaville because Bangui has post-coup security concerns.
“Playing in Bangui would concern us,” admitted Ethiopia striker Getaneh Kebede, “but a lot of Ethiopians will travel to Brazzaville, creating a ‘home’ atmosphere.”
South Africa, playing catch-up since a home draw with Ethiopia on matchday 1, can squeeze through if they overcome Botswana in Durban and the east Africans do not win.
Coach Gordon Igesund was philosophical: “We want Ethiopia to draw or lose, but we cannot worry about what happens in Brazzaville. All we can do is go out and win.”
Tunisia, Cameroon and Senegal need a point each at home against Cape Verde, Libya and Uganda respectively to clinch play-offs places while their rivals must win to snatch top spot.
Congo-Brazzaville need maximum points in Niger to win Group E — any other result opens the door for Burkina Faso or Gabon, who clash in Ouagadougou, to overtake them.
Dead rubbers include Ivory Coast against Morocco in Abidjan with Didier Drogba set for his first competitive international outing since February, Algeria versus Mali in Blida and Egypt’s clash with Guinea in Alexandria.