The commodity is the country's second-largest hard currency earner after coffee and employs some 300,000 smallholder farmers in a nation of over 8 million people.
The country's state-run tea board (OTB) said it collected $2.20 million from the export of 712,736 kg, down from $2.51 million earned in 2012 from the selling of 934,361 kg.
"Buyers were reluctant (and are) waiting to see the direction of the market as it is just the beginning of the year," said OTB's export official, Remy Ndayininahaze.
"This affected revenues," he told Reuters.
Landlocked Burundi exports 80 percent of its tea through a regional weekly auction held in the Kenyan port city of Mombasa.
OTB said despite worries over next week's Kenyan presidential election, trucks continue to carry tea to the Mombasa port. During the last Kenyan poll key trade routes in east Africa were blocked for several weeks as the post-election violence disrupted trade.
Prices at the regional market were stronger because the year/year export average price per kg for Burundi's tea climbed to $3.10 against $2.69 last year.
Tea export revenues rose sharply to $26.3 million in 2012 from $22.2 million in 2011.