* Vietnam's sales slow on robusta volatility
   * Indonesia's robusta discounts narrow as supply tighten
   * Exporters reluctant to offer forward shipment
   
   By Fitri Wulandari
   JAKARTA, Nov 12 (Reuters) - Vietnam's exporters slowed sales after London futures fell from two-year highs, while thinning supplies narrowed discounts of Indonesian Sumatra coffee, dealers said on Friday.
   Rains have slowed the ongoing harvest and drying of beans in Vietnam's Central Highlands coffee belt, while in Indonesia the harvest has ended in the main growing island of Sumatra. 

   "With regular rains and problems in harvesting as well as drying, they don't want to be aggressive as speculators push up prices," said a trader in Singapore, who trades Vietnam and Indonesian coffee. "They are very reluctant to offer shipments for April onwards."
   Vietnam's robusta beans grade two, 5 percent black and broken, was offered at a discount of $160 to London's January contract for nearby shipments, steady from end of October. <COFFEE/ASIA1>
   London's January robusta futures <LRCc2> dropped $53 to close at $1,931 per tonne Thursday on widespread losses in commodity markets linked to a stronger dollar. [SOF/L]
   Robusta futures touched a fresh two-year high of $2,098 per tonne on Tuesday, buoyed by concerns over continuing rains in top producer Vietnam.
   
   INDONESIAN DISCOUNT NARROWS
   Discounts of Indonesian robusta narrowed because of tight supply as most exporters have contracted their stockpiles for forward shipments and as harvest ended.
   Sumatran grade 4, 80 defect for prompt was offered around $70 below London's January contract <LRCc2>, from $100 in end- October, one dealer in Bandar Lampung, the provincial capital of Lampung in Sumatra said.
   "Farmers hardly have any beans. Most of the beans are in the merchants' hands but they only want to sell the beans when prices are higher," the dealer said.
   "Offers for 80 defect for shipments in January-April are very limited. Discounts will be less in coming weeks," the Lampung trader said.
   Indonesia's coffee exporters have stockpiled at least 120,000 tonnes of beans from this year's harvest due to concerns over meeting next year's contracts after heavy rains reduced production. [ID:nSGE67A0C3]
   About 70 percent of stock has been contracted for shipment in early next year before the main harvest starts in April.
   Indonesia is the world's second-largest producer of robusta after Vietnam.
   Shipments of Sumatran robusta coffee from the main port of Panjang in Bandar Lampung fell 17.7 percent to 25,452.40 tonnes in October, from 30,909.21 tonnes a year ago as rains cut supply and traders held back their beans for next year, government data showed.
   Robusta, a more bitter-tasting variety used in instant coffee, accounts for about 85 percent of Indonesia's coffee production. The rest is higher value arabica coffee. (Reporting by Fitri Wulandari; Editing by Manash Goswami)