Monthly output fell for the fourth straight month, declining 24.9 percent in September to 19.3 million kg. Production in the first nine months of 2018 has fallen 4 percent from the same period last year.

"The fall is mainly due to the drought," Sri Lanka Tea Board Director-General S.A. Siriwardena told Reuters.

"But we saw some rain during the last few weeks which will improve production."

Siriwardena expects full-year production to reach 310 million kg.

The Tea Board in August said it may have to downgrade its full-year forecast for tea production after output tumbled 14 percent in that month from a year earlier due to the drought.

Tea is Sri Lanka's top agricultural export and one of the main foreign currency earners for the $87 billion economy.

Earnings from tea exports for the first seven months fell 2 percent to $854.2 million, compared with the same period last year.

Sri Lanka's tea output rose 5 percent to 307.1 million kg last year, recovering from a seven-year low of 292.6 million kg in 2016.

Tea production in 2017 was affected by severe drought followed by flooding and poor application of fertilisers, while a government ban on pesticides and restricted labour added to the sector's problems.