HANOI: Domestic coffee prices in Vietnam edged higher this week, as a potential decline in Brazilian production stoked trader concerns over global supply.

Farmers in the Central Highlands, Vietnam's coffee-growing capital, sold coffee at 32,000 dong-33,000 dong ($1.39-$1.43) on Thursday, compared with 31,400 dong-32,700 dong a week earlier.

"Domestic supplies are getting thinner and we are aware that the output of an ongoing harvest in Brazil is forecast fall sharply," a trader based in the Central Highlands province of Dak Lak said.

"Sales, however, are slow as farmers are not yet happy with the current prices," the trader added.

May robusta coffee settled up $21, or 1.6%, at $1,365 a tonne on Wednesday.

Traders in Vietnam offered 5% black and broken-grade 2 robusta at a premium of $50-$60 to the July contract, compared with a $60 premium a week ago.

Meanwhile, in Indonesia, supplies have started to build up amid a mini harvest there.

"This week we received the highest bean volume so far this year," a trader in Lampung province said on Thursday, noting that the main coffee harvest typically falls around mid-year in the southern parts of Sumatra island.

Sumatran robusta beans were offered with $200 premium to the May and June contracts, unchanged from last week, a trader said.

Another trader offered $200 premium to the July contract, down from $230 premium a week earlier.