( CNN ) -- An oil spill that prompted evacuations from one of Thailand 's most popular tourist spots threatens the country 's tourism and fishing industries , Thailand 's deputy prime minister has warned , amid concerns about the long-term effects of the leak . Deputy Prime Minister Plodprasop Suraswadi said his country was ill-equipped to properly contain the leak , and authorities should seek assistance from neighboring countries such as Singapore , if necessary . He made the comments Tuesday during a trip to Mozambique , according to Thai government spokesman Teerat Ratanasevi 's Twitter page . PTT Global Chemical , Thailand 's largest petrochemical producer , admitted a leak had occurred after the waters at Ao Phrao ( Phrao Bay ) on the popular tourist island of Koh Samet were blackened with oil on Sunday , prompting evacuations of tourists . The company admitted that an estimated 50,000 liters of crude oil had leaked from an offshore pipeline around the area of Rayong 's Map Ta Phut deep sea port Saturday . The company 's president , Bowon Vongsinudom , told CNN Tuesday that he did not know how the leak had occurred . `` That needs a lot of investigation , '' he said . `` It should not happen at all ... anyhow , it already happened therefore we need a lot of investigation by experts . '' He said the clean-up , which also involved the efforts of the Royal Thai Navy and volunteers , was progressing well . `` We can see developments which is much better . We can see now the white water . '' But Greenpeace has said the clean-up efforts are just beginning , and the long-term impacts of the oil were yet to be appreciated . Vongsinudom 's account was `` not the complete picture , '' said Greenpeace Thailand 's program manager Ply Pirom . `` We want to know the real impact of the oil leak , and a comprehensive investigation of the environmental impact is needed . '' The clean-up effort had relied heavily on spraying the oil with dispersant , which made it sink below the water -- out of sight , but potentially harming marine life . `` It 's now under the sea , which will create a long term impact . '' One Thai academic believes the leak could up to twice the size of that admitted by PTT Global Chemical . Somporn Chuai-Aree , a professor of mathematics and computer science at Songklanakarin University , estimated the true size of the leak `` could be from 75,000 liters up to 100,000 liters . '' `` We have to try to get a good estimate of the size of the leak , because it will affect the scale and preparation of the work the company needs to do to get the clean-up done , '' he said .
Oil leak threatens tourism and fishing industries , says Thai Deputy PM . Company responsible says does not know how leak occurred . Greenpeace fears dispersed oil sunk beneath water surface will have ongoing impact . One academic believes leak could be twice size admitted to by company .