KUALA LUMPUR- Malaysia's biggest palm oil producing state of Sabah risks losing 500,000 tonnes of crop from a 14-day blanket closure of plantations in six districts aimed at stemming the spread of the coronavirus, the main growers' group warned on Tuesday.

Earlier the Malaysian Palm Oil Association and Malaysian Estate Owners' Association appealed for a relaxation of the shutdown, saying only three companies out of five large and thousands of smallholders in the state had confirmed cases of infection.

Last week, Sabah expanded the shutdown of palm oil plantations and factories to six districts in the state from three and extended the order until April 14, from March 31, after several palm estate workers tested positive for the virus. 

The state, located in eastern Malaysia, produces about 25% of the country's palm oil.

"Planters on the ground are already lamenting huge crop losses and that their fields have gone unattended and weeds (are) creeping in," the Malaysian Palm Oil Association and Malaysian Estate Owners Association said in a joint statement on Tuesday.

"Any prolonged shutdown will only worsen the situation... This would entail remedial rehabilitation work post Covid-19 which will be a costly exercise," it said.

Malaysian Palm Oil Association chief executive Nageeb Wahad told Reuters the industry estimates a loss of 500,000 tonnes of fresh fruit bunch valued at 430 million ringgit ($99 million)from a 14-day closure.

The associations said some plantations including smallholders have even reported workers leaving due to lack of work. 

Malaysian palm giants, including Sime Darby Plantations and FGV Holdings , have also urged the state to reopen plantations.

Sabah chief minister Shafie Apdal on Tuesday told reporters that he would discuss the shutdown order against plantations and millers with the cabinet on Wednesday.

"Factories with positive coronavirus cases cannot reopen, because I don't want to endanger the public," Shafie said.

The word's second largest palm producer has reported 3,963 coronavirus cases, the highest in Southeast Asia, with 63 deaths.

($1 = 4.3350 ringgit)

(Reporting by Mei Mei Chu; Editing by Emelia Sithole-Matarise) ((meifong.chu@thomsonreuters.com; +603-2333-8035; Reuters Messaging: @meixchu on Twitter))