Coffee trading in Vietnam remained lacklustre this week as stockpiles dwindled and supply from the new season is unlikely to be available in around a month.

Farmers in the Central Highlands, Vietnam's largest coffee-growing area, sold coffee at 34,000 dong ($1.47) per kg on Thursday, slightly lower than a week ago.

The 2019/20 season started on October 1 but traders said the market would stay muted until at least early November when new beans arrive.

"There are almost no beans left from the 2018/19 season," said a trader based in the Central Highlands. "Fresh beans won't arrive in bulk until the second week of November."

Traders in Vietnam offered 5% black and broken grade 2 robusta at $180-$200 premium per tonne to the November contract on Thursday, unchanged from a week ago.

"Trade, supply and demand are all dull at the moment," said an analyst, also based in the region.

Vietnam's coffee exports in the first nine months of this year fell 12% from a year earlier to 1.27 million tonnes or 2.12 million 60-kg bags, according to government data.

Meanwhile, Indonesia's grade 4 defect 80 robusta beans were offered at premiums of $210-$215 to the November contract, wider than $200 last week, a trader in the Sumatran province of Lampung said.

Another trader in the province said trade had slowed down this week as the main harvest came to an end. Indonesia's robusta coffee bean exports from Sumatra rose 75% in September from the same month last year, local trade office data showed on Tuesday.