The Reagan administration is considering a Chadian government request for the supply of U.S.-made Stinger antiaircraft missiles following what appears to have been the most devastating Libyan military defeat this year at the hands of Chadian forces, U.S. officials said yesterday.

Both State Department and Pentagon officials said the United States was monitoring closely the escalation of fighting that has spilled over into southern Libya, and indicated additional emergency aid might be forthcoming, including Stingers, if the situation warrants it.

The administration already has sent an additional $32 million in military assistance to Chad this year and has provided Chad's Army with Redeye antiaircraft missiles. The normal U.S. military aid program was $5 million at the start of this fiscal year.

Chadian President Hissene Habre first asked for the Stingers during a visit here June 19-20, which included a meeting with President Reagan. Reagan assured the Chadian leader of strong U.S. backing for his efforts to oust Libyan troops from the disputed, 70-mile-wide Aozou strip in northern Chad.

Pentagon spokesman Robert Sims noted yesterday there was speculation that the Stinger was under consideration for Chad, but said it would be "inappropriate" for him to discuss any "specific {military} hardware."

However, other administration sources said the Stinger, which has proven effective against Soviet aircraft in Afghanistan, was being considered as part of additional U.S. aid to Chad.

The sources also said that a Hawk surface-to-air missile used by French forces Sunday to shoot down a Libyan Tu22 bomber over the Chadian capital of Ndjamena was not provided to Chad by the United States but had been sold earlier to France.

Meanwhile, administration officials sought to play down reports from Paris that the United States and France were pursuing different policies in Chad, with Washington urging Habre to take back the Aozou strip.

French Foreign Minister Jean-Bernard Raimond was quoted by news agencies as saying the United States was "perhaps giving Chad advice that is different than ours, but what is best for the Chadians and Africans is the French policy in Africa."

The French have supported international arbitration to settle the Chad-Libya dispute over the Aozou strip. Yesterday, French President Francois Mitterrand said France regretted the escalation in fighting and hoped it would end immediately.

On the other hand, State Department spokesman Charles Redman reiterated U.S. support for Chadian efforts to retake the Aozou strip, saying that the issue at stake in the current fighting was Chad's "territorial integrity and sovereignty."

Redman denied that the administration had "advised" the Chadians to "go north" either to recapture the disputed strip or to carry out last Saturday's lightning attack on the big Libyan air base at Matan as Sarra, 60 miles inside Libya.

But he did not condemn Chad's raid across the border, describing it as "a limited operation against a base from which it {Chad} was suffering aggressive Libyan attacks."

U.S. officials previously have said they hope the heavy losses repeatedly inflicted on the Libyan Army by the Chadians will spark an uprising against Libyan leader Moammar Gadhafi and lead to his demise.

The Chadian government released its first assessment of Libyan losses there, saying that 1,713 Libyans were killed and 309 taken prisoner.

These losses, if accurate, would be even greater than those Libya suffered last March 22 when the Chadians captured the Libyan air base at Wadi Doum in northern Chad and seized an estimated $500 million in Soviet-supplied arms.