BEIRUT, Lebanon (AP) _ Christian army commander Gen. Michel Aoun was quoted today as saying he was willing to hold a round table conference with Moslem leaders to determine Lebanon's future government.

''I am ready any time to discuss Lebanon's future at a round table with leaders of the other side,'' Aoun said in an interview published by the Paris- based Arabic magazine Koll el-Arab.

He made no mention of his previous condition that any Christian-Moslem negotiations on political reforms should be preceded by the withdrawal of the Syrian army from Lebanon.

Aoun's remark was broadcast by Christian and Moslem radio stations as his 20,000 mainly Christian troops traded sporadic artillery and tank fire across Beirut's dividing Green Line and in hills above the capital.

No casualties were reported. By police count, 784 people were killed and 2,126 wounded since Aoun's confrontation with the Syrians broke out March 8.

Police said Syrian gunners in Moslem west Beirut and in north Lebanon pounded the coast of the Christian port of Byblos with 100 shells and rockets overnight to turn back three ships carrying food to the beleaguered Christian enclave.

The splinter Moslem army command issued a communique today claiming its gunners scored hits on all three ships and ''prevented them from unloading arms and ammunition.''

But sources at Aoun's command ridiculed the claim, saying Moslem army units in west Beirut do not possess the long-range guns needed to hit Byblos, 20 miles north of Beirut.

The poorly equipped Moslem troops of the army - estimated at 22,000 - are largely scattered in remote areas in north, east and south Lebanon with only about 4,000 in west Beirut. They have played no active role in the Syrian- Christian confrontation.

The Syrians, who maintain 40,000 troops in Lebanon under a 1976 peacekeeping mandate from the Arab League, are bent on preventing arms supplies from reaching the blockaded enclave, home to 1 million Christians.

Beirut media reports said today that the dispatch of French warships to the eastern Mediterranean was aimed at breaking the Syrian siege.

The independent newspaper An-Nahar quoted unidentified sources as saying the French flotilla would run the gauntlet of Syrian shellfire and ensure the arrival of arms and fuel supplies to the enclave.

France has dispatched the aircraft carrier Foch and destroyer Duquesne to take positions off Lebanon's coast along with a navy hospital ship and fuel tanker for the declared purpose of evacuating 7,000 French passport holders from Lebanon if the fighting worsened.

''France is just giving a humanitarian excuse for its upcoming military intervention,'' An-Nahar quoted an unidentified ''high-ranking source'' in Beirut as saying.

The French naval moves provoked a Moslem uproar. Hezbollah, or Party of God, Iran's main Shiite Moslem ally in Lebanon, has threatened anti-French suicide bombings.

Druse warlord Walid Jumblatt, whose 6,000-strong militia is backing the Syrian army, warned that a French intervention would hurt Christian minorities throughout the Middle East.

The Revolutionary Justice Organization, an underground group holding two American hostages, warned in a statement released Sunday night that their lives would be in peril if the French navy intervened in Lebanon.

''America, which is spurring France on, should realize that any foolhardiness by the French fleet will expose the life of its hostages to danger,'' the statement said.

The group holds Joseph Cicippio, 58, acting comptroller of the American University of Beirut who was kidnapped Sept. 12, 1986, and self-styled writer Edward Austin Tracy, 58, who was abducted Oct. 21 the same year.

In Sidon, provincial capital of south Lebanon, a freighter that has been smuggling food supplies and vegetables to the Christian enclave, was blown up by three bombs at the city's harbor at dawn today, police said.

The vessel sank but its seven-man Lebanese crew swam to shore unharmed, according to a police spokesman.

This was the fourth freighter to be blown up in Sidon for smuggling food to the Christian enclave. Three were wrecked by similar explosions in June.