BANGKOK (REUTERS) - Thailand's economy may only expand 3.0-3.5 per cent in 2014 if political protests continue and the government has to postpone planned infrastructure investment, the deputy prime minister and commerce minister said on Monday.

"If the protests go on and big public works such as the 2 trillion baht infrastructure projects and water management projects are postponed, GDP growth would fall to just 3.0-3.5 per cent," Niwattumrong Boonsongpaisan told reporters.

The government had forecast GDP growth of 4.0-5.0 per cent this year, he said. On Dec 26 the finance ministry forecast 3.5 per cent if the protests were prolonged.

Niwattumrong said exports could grow 5 per cent this year, as forecast.