By Lewa Pardomuan
   SINGAPORE, Aug 6 (Reuters) - Exporters in Vietnam, the world's largest robusta coffee producer, have defaulted on the shipment of at least 30,000 tonnes of beans since March because of losses on London futures, dealers said on Thursday. 

But second-largest producer Indonesia may fill the supply gap, dealers said, after some of the beans seized by creditors from an ailing exporting firm were released in the domestic market.
   Fears of defaults from Vietnam have gripped the coffee market in Southeast Asia in recent weeks, with dealers accusing farmers and shippers of holding back on stocks before the next harvest in late October.
   "One shipper has defaulted on the shipment of more than 5,000 tonnes of beans to my company," said a dealer at an international trading company who trades Vietnamese and Indonesian beans.
   "The amount of defaulted shipments from Vietnam may be 30,000 tonnes and there's also a possibility that 50,000 tonnes have been washed out since March," he said.
   Second-month November London coffee futures <LRCc2> dropped to an all-time of $1,250 a tonne in June, and while they have recovered to around $1,500 a tonne now, are still well below the high for the year of $1,745 seen in January. 
   "This could have a very big impact on the market in London. 50,000 tonnes may have been washed out already, so it means we are not expecting fixing for delivery against September," said another dealer, referring to London's front-month contract.
   "The farmers believe the price should go up. That's why they are holding back their beans. You can say 20,000 to 30,000 tonnes may have been defaulted," he said.
   The market may see more supply neighbouring Indonesia, where creditors are expected to sell beans seized from the country's biggest exporter, PT Tripanca, with more than 17,000 tonnes already auctioned. [ID:nSP535818]
   Tripanca failed to settle a dispute over payment with banks, leading to the seizure of around 60,000 tonnes of beans. But only 40,000 tonnes, valued at around $60 million at current futures prices, would be sold, said dealers.
   "If the Vietnamese don't want to sell, then I think the Indonesians should sell the 40,000 tonnes as soon as possible because the price is still above $1,500. It will be great for them," said the second dealer.
   "If they also wait for better prices like the Vietnamese, it may happen or it may never happen at all," he said.
   Beans for prompt shipment were offered at a discount of $60 under London's September contract <LRCU9>, which fell $21 to close at $1,499 per tonne on Wednesday, driven by a pullback in other soft commodities. [SOF/L]
   Robusta is either blended with arabica for a lower-cost brewed coffee or processed into instant coffee.