An unprecedented effort by Adolph Coors Co. to increase beer sales by promising large grants to Latino groups has severely split Hispanic leaders throughout the country.

An Oct. 29 agreement between some Latino organizations and the company, which has been the target of a union-organized national boycott for the last seven years, promised more Coors minority hiring, $500,000 in annual grants and even more money for Latino-owned businesses and banks if beer sales increase in minority neighborhoods.

Edward Bernaldez, national chairman of the American GI Forum, a Hispanic veterans group that signed the five-year agreement, today called it a "tremendous step forward."

But Virginia Reade, regional director of the Mexican-American Political Association (MAPA), sharply criticized Coors for "giving an added incentive to drink more alcohol in a community that already has too much consumption of alcohol, particularly among our teenagers."

The agreement, reached after Coors discovered its share of sales to Latinos in California had dropped from 40 to 17 percent, has produced dissension even within well-organized national Hispanic groups. Arnold Torres, national executive director of the 115,000-member League of United Latin American Citizens (LULAC), said his headquarters decided to take no position on the agreement after discovering some local chapters favored it and others opposed it. Larry Amaya, regional director of the American GI Forum here, told a press conference Monday he opposed the agreement because it "makes us out to be Coors salesmen." But Bernaldez, the 136,000-member group's El Paso-based chairman, said today that "Larry Amaya does not speak for this organization."

The dispute grows out of a lengthy and sometimes controversial campaign by the Colorado company to counter an unfavorable image in minority communities caused by a lingering union dispute and the political activities of some Coors family members.

The AFL-CIO mounted a boycott of Coors products shortly after a local of its Brewery Workers affiliate struck the Coors plant in Golden, Colo., in 1977, according to John Meadows of Coors. In 1978 the majority of non-striking workers voted to decertify the union, and boycott activities increased.

In 1979, groups such as the GI Forum and LULAC were persuaded to drop their support of the boycott when the company began hiring and promoting more Hispanics.

Murray Seeger, spokesman for the AFL-CIO, said the company continues to pursue anti-union policies and has tried to blur its image with grants to minority groups, which he called "the height of hypocrisy."

At a Monday press conference here, several officials for Latino groups criticized Coors family donations to the John Birch Society and other groups they said favored anti-labor and anti-minority causes. Coors spokesman William Pauli called the criticism "ludicrous," because the only donation he was aware of was $500 from President Joseph Coors to the John Birch Society nine years ago.

The boycott, Meadows said, "has hurt, but it's difficult to assess how much." The once-regional company has now expanded its sales into 37 states, more than making up with expansion business it lost in some market areas because of increased competition and the boycott.