Chadian officials are worried that France is willing to allow a "de facto partition" of the country into Libyan and French spheres, along the lines of the two-week-old informal cease-fire, a western diplomatic source said today.

On the eve of an expected major statement by President Francois Mitterrand on French policy on Chad, the country's concerns were publicly raised in an editorial in the official daily bulletin Info-Tchad. The author, Pierre Mahamat, alleged that some officials "in Paris have been seduced by the idea of this miraculous solution that will resolve all the problems: the dismemberment of Chad."

Information Minister Mahamat Soumaila, asked whether he felt the two-week-old undeclared cease-fire could result in a partition leaving Libya in military occupation of the northern third of Chad, said, "A lot has been said about partition, but partition depends on the reaction of France" to Libya's territorial conquests.

French government spokesman Max Gallo said in Paris today that details of French policy will be contained in a Mitterrand interview to be published Thursday by the newspaper Le Monde.

Mitterrand discussed the Chadian situation with his Cabinet today, and Gallo said afterward that France had built up a "position of force" in Chad to enable discussions toward a solution to start, the Manchester Guardian reported from Paris. Gallo said France saw the trouble in Chad as an African affair that should be solved in the framework of the OAU.

A western diplomatic source said the government of Chadian President Hissene Habre, too weak to repulse Libya's well-equipped Army on its own, is afraid a partition "could become acceptable to France and the international community."

In a cautious reply to questions, however, Soumaila said, "We are worried about the annexation of all of Chad by Libya, not just one part."

Chad's worries grew today when it became known that Mitterrand had sent private envoys to Tripoli to meet with Libyan leader Col. Muammar Qaddafi and to Addis Ababa to meet with Ethiopian President Mengistu Haile Mariam, this year's chairman of the Organization of African Unity. Roland Dumas, France's envoy to Tripoli, had been in Libya last week as well, but this was apparently the first time Mitterrand had sent Maurice Faure, the chairman of the parliamentary foreign affairs commission, to Addis Ababa.

It is considered unlikely, however, that the OAU would agree to the present stalemate in Chad or an eventual partition. A major principle of the organization is the inviolability of colonial boundaries inherited at independence. OAU leaders fear that if this principle is not upheld Africa would be torn by more wars, such as the unresolved conflict between Ethiopia and Somalia.

Western diplomatic sources said up to 3,500 regular Libyan Army soldiers now occupy the northern third of Chad with headquarters at the rebel-held town of Faya Largeau. With them are approximately 2,000 to 3,000 rebel forces from Chadian factions, nominally led by Goukouni.

More than 1,000 French troops are dug in alongside Habre's force of fewer than 4,000 men in eastern and western Chad. There also are 2,500 Zairian troops here backing Habre's government.

There have been no reports of fighting since Faya Largeau fell to rebel forces on Aug. 10, and Libya stopped bombing the government-held oasis of Oum Chalouba on Aug. 12. Today Soumaila denied reports that there was a "skirmish" between rebel and government forces near Oum Chalouba.

The Manchester Guardian added from Paris:

France has stepped up its diplomatic efforts to settle the Chadian civil war, and Gallo said today that Mitterrand intended to continue a "prudent and determined" policy.

Mitterrand outlined the French position at the first Cabinet meeting for three weeks, during which Faure's mission was discussed. Faure is to meet Mengistu in Addis Ababa to discuss possible OAU intervention and mediation similar to that during the civil war three years ago.

Paris wants to avoid any direct involvement in a settlement that would lead to accusations of neocolonialism. It prefers the OAU to raise questions such as possible partition or confederation of Chad or the reconstitution of a multifaction government such as that run by Goukouni before he was overthrown by Habre. Ababa to discuss possible OAU intervention and mediation similar to that during the civil war three years ago.

Paris wants to avoid any direct involvement in a settlement that would lead to accusations of neocolonialism. It prefers the OAU to raise questions such as possible partition or confederation of Chad or the reconstitution of a multifaction government such as that run by Goukouni before he was overthrown by Habre.