Weeks of drought and heat have hit Brazil's soy and corn production, but the agriculture ministry on Tuesday still predicted a record 2014 harvest.

Corn production is set to total 75.5 million metric tons, down from a January estimate of 79 million, state food supply agency Conab said in its monthly report.

Soy production will be 90 million tons, just off a January forecast of 90.3 million, and still 10.4 percent higher than last year, Conab said.

For soy, grain and rice combined, Conab now expects 2013 to show a 3.6 percent increase overall, to 193.6 million tons.

Last month it had forecast a combined total of 196.7 million tons -- but January saw very low rainfall in much of the giant country.

Brazil's Institute of Geography and Statistics gave its own 2014 forecast of 193.9 million tons, three percent up on last year's 188.2 million tons, which was, itself, the best return on record.

Conac chairman Rubens Rodrigues dos Santos played down the effects of low rainfall, saying "favorable (production) expectations are confirmed."

Consultant Rafael Ribeiro told AFP: "There has been a lack of rain, and heat affecting the south, in particular, has begun to have an effect, which could lead to further downward revisions in forecasts."

But, like the official agencies, he still forecast a record yield.

Brazil is the world's number one soybean exporter and also second-biggest exporter of corn.