BANGKOK (REUTERS) - Thailand's economy grew 3.3 per cent on an annual basis in the third quarter, the National Economic and Social Development Board said on Monday (Nov 19), missing a 4.2 per cent expansion forecast by economists.

South-east Asia's second-largest economy showed no expansion in July-September from the previous three months on a seasonally adjusted basis, contrary to expectations of some growth in spite of softer exports and tourism.

The quarterly reading was the weakest since the first quarter of 2014, when the economy shrank 0.4 per cent.

The forecast in a Reuters poll for July-September was 0.6 per cent, compared with a revised 0.9 per cent in the previous three months.

The planning agency on Monday downgraded its 2018 gross domestic product growth forecast to 4.2 per cent instead of the previous 4.2-4.7 per cent range. It now expects exports to rise 7.2 per cent this year, rather than 10.0 per cent.

For 2019, the agency predicts growth of 3.5-4.5 per cent, with exports rising 4.6 per cent.

Analysts polled by Reuters predict GDP growth of 4.5 per cent this year and 4.2 per cent in 2019.

Last year's pace was 3.9 per cent, the best in five years.