The Organizatiton of African Unity's conference on the future of Chad broke up today beause of sharp disagreement over the issue of Libyan intervention in that central African nation.

The meeting ended here after a minority of the group refused to call for the immediate withdrawal of Libyan troops from Chad.

Libya's leader, Col. Muammar Qaddafi, has denied that there are large numbers of Libyan soldiers in Chad and claims he has sent only military aid and technical advisers to that war-torn nation.

Yet there is growing concern among African countries, and particularly among those that border Chad, that Quaddafi will export his radical brand of Islamic revolution to the mainly Moslem populations of central Africa. Recently, three black Arcian states -- Senegal, the Gambia and Ghana -- cut diplomatic ties with Libya amid reports of Libyan attempts to destabilize their governments.

Thus, when the conference opened yesterday, most of the nations participating seemed to favor condemning the Libyan presence in Chad.

Today's communique indicated that things turned out quite differently.

Issued two hours late, at noon today, the final communique omitted the draft statement's ninth point, proposed by the seven nations that later walked out of the conference. The point demanded "the unconditional withdrawal of all foreign troops from the territory of Chad."

The communique as released by the remaining nations ended with point eight, which urged that an independent monitoring force be alowed to oversee the future elections in Chad.

The final text was approved by Nigeria, Sierra Leone, Congo and Benin, in addition to Chad and Libya. The majority of the nations attending -- Sudan, Senegal, Togo, Guinea, Cameroon, the Central African Republic and Niger -- walked out of the conference without voting.

At least two prominent heads of state at the meeting, Nigeria's Shehu Shagari and Sierra Leone's Siaka Stevens, seemingly reversed their earlier public postions that removal of Libyan troops was a prerequisite to the reconstruction of Chad.

At yesterday's opening session, Stevens, who is also this year's OAU chairman, said an end to Chad's civil strife could not be found until "all foreign forces in Chad" were removed. The governments of Nigeria and Sierra Leone are reputed to be relatively conservative. Congo and Benin, the other two countries joining Chad and Libya in approving the communique, are Marxist. Benin has received substantial financial aid from Libya.

Observers said that this conference, the fifth on Chad to be held in Nigeria, represented a victory for Libya, as the outcome indirectly endorsed the Libyan presence in Chad and confirmed the legitimacy of the Libyan-backed regime now ruling that country.

Chad has been ruled by a weak transitional government headed by Goukouni Oueddei since November 1979. The transitional government was established during peace talks in Lagos in August 1979, attended by all 11 of the country's guerrilla factions, 10 of which are Moslem. The 11-faction transitional government was supposed to hold elections to end the scrambling for power that has crippled Chad since the mid-1960s.

But in March, fierce fighting broke out between the forces of Oueddei and the transitional government's defense minister, Hissene Habre. Being evenly matched, niether side gained much during nine months of fighting. Then, say Western intelligence reports, massive Libyan military aid and troops were brought in to help Queddei's guerrillas. The fighting ended last week with Habre's forces fleeing the Chadian capital of Ndjamena into the desert countryside.

Internal events have put Nigeria, black Africa's most powerful state, into a particularly sensitive position in its dealings with Livya. Begun apparently by an Islamic fundamentalist sect, an outbreak of violence last Thursday in the northern city of Kano led President Shagari to authorize the Army to aid police in putting down the riot. Reports reaching Lagos indicate that as many as 300 persons died in the violence. Moslems in northern Nigeria have traditional, ethnic and family ties with the entire central region of Africa, including Chad.