JOHANNESBURG, March 16 (Reuters) - Monday's decision to appoint Ghana and Nigeria as the co-hosts of next year's African Nations Cup finals in place of Zimbabwe has meant an overhaul in the format of the tournament's qualifying competition. The Confederation of African Football (CAF) has annulled the preliminary round records of the new hosts and allowed Zimbabwe to participate in the qualifying competition.

Zimbabwe were stripped of the right to host the finals, set for January 23 to February 13 next year, after falling behind with the contstruction of venues for the 16-team event and failing to provide financial guarantees.

Ghana and Nigeria now qualify automatically as hosts. Holders Egypt are also in the final field. Here is an overview of the qualifying competition, which is at the halfway stage: Group one: Ghana's results are removed from the record, which means Cameroon now lead the group. The winners will automatically qualify for the finals but the runners-up now have to go into a play-off group with Zimbabwe and the runners-up from group five. Cameroon have four points from two matches, Mozambique three and Nations Cup newcomers Eritrea one. Group two: Morocco are leaders in a group which is also likely to have just three participants after Sierra Leone's failure to play a match against Guinea last month. Sierra Leone face possible disqualification. The top two will go through to the finals, with Togo and Guinea likely to have a tight fight to decide the other qualifying spot. Group three: Congo, with seven points from three matches, are the surprise leaders after their recent win over the Ivory Coast, who lie second, one point behind. Mali and Namibia each have a game in hand but are already considerably off the pace.

The top two qualify for the finals. Group four: South Africa look solidly on course for the finals with seven points from their opening three games but the race for the other qualifying places promises much intrigue. Mauritius scored a shock away win over Angola in their last game and lie second with four points. Angola and Gabon have three points each.

Group five: Nigeria's record is expunged, leaving Burkina Faso in pole position for the one automatic qualifying place. The runners-up go into the play-off group (with Zimbabwe and the second-placed finisher in group one) and this means a better chance for both Burundi and Senegal, who have had a languid start to the qualifying campaign.

Group six: Two successive away wins have put Zambia in front with seven points. Madagascar and the Democratic Republic of Congo are tied for second place with four points, while Kenya look out of the race with a solitary draw to their credit. The top two qualify.

Group seven: With Ghana now out of the preliminaries, Tunisia are the only team with a 100 percent record after three matches. The race for the other qualifying berth sees Liberia with four points, Uganda with three and former African champions Algeria with just one. The key match comes when Algeria entertain Liberia on April 9.

The next round of qualifiers will be played on the weekend of April 9 to 11. The preliminary competition is scheduled to end in June, although the dates for the new proposed play-off group have yet to be announced by CAF.