Four million tons of wheat that the United States has kept stashed away for three years for emergency international famine relief suddenly has provoked voracious hunger here at home.

American millers and bakers think it's grist for profit and are kneading Congress vigorously. School-lunch administrators see it as a nutritious antidote to the stomach aches caused by Reagan administration budget cuts.

With recession assistance and surplus commodity giveaways in vogue on Capitol Hill, lawmakers are being urged increasingly to tap the international famine reserve as a quick and inexpensive way of feeding needy Americans.

And groups such as Bread for the World and other allies in the world-hunger lobby are pushing just as hard to persuade Congress to keep its hands off the 4-million-ton famine reserve and find other ways to feed the hungry in the United States.

The newest round of push-and-pull is occurring at the House Agriculture Committee, which is scheduled to consider today a surplus-commodity distribution bill that would permit more domestic use of the famine reserve, which was earmarked by Congress in 1980 for Third World distribution.

"It is hard to argue against using that wheat to feed hungry people here," said Nick Mottern, a lobbyist for Bread for the World. "But if the reserve is to become a sort of revolving fund, the wheat won't be there when the world needs it . . . . We have hungry people here, but we say the United States has the wealth and capacity to meet the need head-on--and not by going into the famine reserve."

Howard Hjort and Dale Hathaway, high-level Agriculture Department officials during the Carter administration, when the famine reserve was created, agree with Mottern. "It is a mistake to tap the reserve. We worked very hard to establish it," Hjort said. The bill represents "a facade--a belief that if we take it from government hands, it will have no cost. Replenishment will be expensive."

Millers and bakers, however, see profit in the possibility of freeing the famine reserve for domestic use. School lunch and institutional feeding programs that get the wheat will need it processed into flour and baked goods, for which someone will have to pay.

"We all agree the famine reserve should be replenished," said Robert Wager of the American Bakers Association. "But we think this program could help everyone, especially those voluntary agencies that have had budget cuts."

The reserve was set up after President Carter imposed a partial embargo on grain sales to the Soviet Union and surpluses developed. Generally low prices, ample supplies and the absence of a Third World emergency have kept the reserve intact since then.

But Congress set a precedent for going into the reserve earlier this year when it passed the jobs assistance bill, directing that some of the wheat be processed into flour and distributed here.

Then the Senate Agriculture Committee, in an export trade bill that has not yet gone to the floor, authorized use of the reserve wheat as a bonus to foreign buyers to help stimulate agricultural sales abroad.

In both instances, as well as in the measure pending in the House, the secretary of agriculture would be required to bring the reserve back to the 4-million-ton level later on. However, he would have to go through the tortuous budget process to get the funds