The U.S. Embassy in Brazil said yesterday the country is "highly uncertain what damage has occurred, if any" to Brazilian coffee trees from Monday's frost.

But, agricultural attache Leon Mears said, unless more unusually cold weather hits, this year's coffee crop in Parana state, now being harvested, should not be affected.

Mears said in a telephone interview there were conflicting reports in Brazil over the severity of the frost and that it would be three to four days, before reliable assessments can be made. Mears quoted the Brazilian government - as saying there was "significant" damage in Parana while the secretary of agriculture for that state was saying there has not been any damage.

Either way, an Agriculture of ficial in Washington said, any losses should have relatively little impact on coffee production. The U.S. Agriculture Department has estimated that Parana will produce only 2 million bags of coffee this year out of a total U.S. estimated crop of 16 to 17 million bags. He added that while Brazilian estimates are about 13 to 14 million bags, the two governments had agreed on 2-million-bag estimate for Parana.

A Brazilian frost in July of 1975 killed to many trees that the country's exports are coming from surplus stocks laid in years ago. What the coffee-drinking world fears now is that any further major damage, with reserves depleted, will leave Brazil unable to meet world demands. The country supplies about one-fourth of the world's coffee beans, and that is why coffee prices have scored.

Reports of the Monday frost touched off a price rise on Tuesday. But Mears said, "The best information is that there is not extensive damage to coffee trees in Parana," the only coffee-growing area hit by the frost.

A spokesman for the Brazilian Coffee Institute in the United States said that near-freezing temperatures combined with high winds for a "black frost," which can cause leaves to die. Many of the trees in Parana, he said, are young trees planted to replace those lost in the 1975 freeze.

"It could be substantial, it could be meaningless," said the spokesman. "They (in Brazil) say sit tight."