Thailand's economy contracted 1.8 percent in the first quarter and is projected to shrink further to 5 percent to 6 percent this year from a growth of 1.5 percent to 2.5 percent projected in February, said Thailand's national economic planning agency, the National Economic and Social Development Board (NESDB).

"The quarterly contraction was the first since 2014 and the Thai GDP will further drop in the second quarter due to the COVID-19 impact," NESDB Secretary General Thosaporn Sirisumphand said on Monday.

The NESDB also forecasts Thailand's total exports to drop by 8 percent.

"However these projections are based on the assumptions that the virus is contained by the second quarter and the economic and tourism activities return to normal in the latter half of the year," said Thosaporn.

The agency also cut its projection for this year's exports and foreign tourist numbers, the main drivers of Thailand's growth.

Thosaporn said that due to the effects of the COVID-19 pandemic, the tourism industry could lose at least 150 billion baht (4.68 billion U.S. dollars) in revenue.