Coffee output in Brazil, the world's chief exporter, will slide this year after the worst drought in decades, agricultural agency Conab said Tuesday.

The drought hampered the development of plants, causing the arabica crop to plummet 16.1 percent, Conab said.

"Brazil should this year produce 45.1 million 60kg bags" of arabica and robusta crops, the main kinds of bean cultivated for drinking, Conab indicated.

"This represents a drop of 8.16 percent .. compared with the last harvest.

"The change is down to the arabica variety, which fell 16.1 percent," added Conab, an offshoot of the ministry of agriculture.

Latest forecasts are for an arabica crop of 32.1 million bags, the variety accounting for a three-quarters share of Brazil's overall harvest.

Conab blamed a severe drought which lasted for more than two months early this year for the slump.

Frosts had already damaged plantations in southern Parana state last year before the drought dealt a second blow to Brazil's two-year coffee-growing cycle.

This year's fall-off in production will be felt more keenly given that output in even-numbered years is larger than in odd-numbered ones.

Production of the harsher-tasting Robusta crop should fill 13 million bags this year.

"That is an increase of 19.9 percent thanks to a rise in productivity and favorable climactic conditions in (southeastern) Espirito Santo state, this variety's main producer," Conab said.

With 2.2 million hectares (5.4 million acres) of plantations, Brazil is the world's leading exporter.

The South American giant's annual output is some 2.5 billion kilograms (5.6 billion pounds) some three times the output of second-ranked Vietnam.