Farmers in the Central Highlands, Vietnam's largest coffee growing area, sold coffee at 35,000 dong ($1.51) per kg on Thursday, unchanged from a week ago.

"There's not much coffee left out there and so we can't sign new export contracts for delivery during the rest of the current crop year," a Central Highlands-based trader said.

The current 2018/19 crop year will officially end at the end of September. Farmers will start the new harvest in October.

Traders in Vietnam offered 5pc black and broken grade 2 robusta at a $90 per tonne premium to the November contract, narrowing from $110-$120 last week.

Government data released late last week showed Vietnam's coffee exports in the first half of this year fell 10.6pc from a year earlier to 928,000 tonnes.

June exports were estimated at 150,000 tonnes, up from 146,220 tonnes in May.

September robusta coffee settled up $11, or 0.8pc, at $1,455 per tonne on Wednesday.

Data from the International Coffee Organisation released on Monday showed global coffee exports rose 19.4pc year-on-year in May.

Meanwhile, Indonesia's grade 4 defect 80 robusta beans were offered at a $180 premium to the September contract, flat from last week, a trader in the Sumatran province of Lampung said.

"Trading volume remains steady, though I don't see any significant improvement in demand," the trader said.

Coffee shipments from Lampung in June fell 53pc from a year earlier to 3,542.4 tonnes, according to data from local trade office.