Thailand's big-ticket infrastructure investment worth 1.5 trillion baht is expected to raise the country's GDP for three years during the construction period, says the Fiscal Policy Office (FPO).
The size of the benefit to Thailand's economic output will depend on the investment budget disbursed each year, said director-general Krisada Chinavicharana.
The government is priming transport projects in hopes they will attract much-needed private investment, a crucial engine for sustainable economic growth.
Construction contracts for all 20 big-ticket infrastructure projects are expected to be signed this year, with 10 in the first half and 10 in the latter half.
Projects with contracts already signed and building under way include the 185-kilometre one-metre-gauge double-track rail network linking Jira junction in Nakhon Ratchasima to Khon Kaen, the Pattaya-Map Ta Phut motorway, the Bang Pa-in-Saraburi-Nakhon Ratchasima motorway, improvements to Laem Chabang deep-sea port and container terminal development at Laem Chabang.
Mr Krisada said investment in infrastructure megaprojects was expected to pick up in pace, as Prime Minister Prayut Chan-o-cha recently invoked Section 44 to allow bidding on large-scale projects to be opened before an environmental impact assessment (EIA) study is conducted.
While the move is meant to accelerate investment in the infrastructure projects, they will still require an EIA, he said.
Meanwhile, the FPO will cut its GDP forecast for this year from 3.7%, but said the new figure will remain above 3%, Mr Krisada said.
The Bank of Thailand's Monetary Policy Committee in March trimmed its 2016 GDP growth forecast to 3.1% from 3.5% in anticipation of an export contraction. The central bank's latest economic growth forecast is based on an estimated 2% contraction in outbound shipments.
The Asian Development Bank also slashed Thailand's GDP outlook for this year to 3% from 3.5%, citing gloomy global prospects. Fragile growth in big industrial economies and China's slowdown are the main factors for the revision.
The Manila-based multinational lender forecasts Thai merchandise exports to contract by 1%, down from flat growth forecast previously.