Thailand's economy shrank by a record 6.1% in the last three months of 2008 amid plummeting exports and tourism.
The National Economic and Social Development Board said the contraction was the largest since records began in 1993. The NESDB said the economy might contract 1% in 2009.
The BBC reports the economy has been hit by the global downturn and political unrest at the end of 2008. Anti-government protesters closed Bangkok's airports, hitting tourism, one of the key sectors of the economy.
Compared with the same period a year earlier, the economy contracted by 4.3% in the fourth quarter.
Exports, which account for more than 60% of Thailand's gross domestic product, dropped 9.4%.
The NESDB also forecast that exports would fall 13.1% in 2009 after growing by 16.8% in 2008.
The Bank of Thailand has reduced its key lending rate by a combined 1.75 percentage points to 2% since December.