Premiums of Indonesia's grade 4 defect 80 robusta in main coffee growing province Lampung fell to $130 a tonne to London's July contract, from a $140 premium level cemented in the previous six weeks, a trader said.

"Trade was very busy, especially on Monday. Up to 300 trucks were transacted, and around 100 trucks on Thursday," the trader said. One truck typically carries 8-10 tonnes of beans.

Lampung has a mini harvest around March and April with the main harvest expected around mid-year. The area exported 4,280 tonnes of coffee beans in March, down 75 percent from a year earlier but up slightly from February.

In Vietnam, the world's second biggest coffee exporter, trading was subdued as sellers preferred to hold on to stock, citing unattractive prices, while importers eyed incoming supply from Indonesia and top coffee producer Brazil.

"The market is not really that upbeat; some exporters sold this week but only at a small amount. The coffee agencies are still holding beans, and demand is weak," said a Ho Chi Minh City-based trader.

Farmers quoted beans at 37,300-37,600 dong ($1.64-$1.65) a kilogram in Dak Lak province, up slightly from 36,800-37,000 last week, reflecting London prices, traders said, adding farmers would sell strongly if price hits 40,000 dong.

Vietnamese traders quoted the 5 percent black and broken grade 2 robusta at a discount of $50 to the July contract, tightening slightly from a discount of $70 a week ago.

Traders forecast coffee exports from Vietnam in April would reach 100,000-140,000 tonnes (1.7-2.3 million 60-kg bags), down from March's exports estimate of the beans of 180,000 tonnes.

The country exported nearly 130,000 tonnes in February, when it had a week-long holiday break, and shipped around 200,000 tonnes of coffee in January.