The Finance Ministry will need about one month to set priorities for the 53 infrastructure projects under the government's 2-trillion-baht investment plan.
The projects' readiness will determine which ones will be put on the front burner, said Public Debt Management Office (PDMO) director-general Chularat Sutheethorn.
The Finance Ministry's joint efforts with the Transport Ministry to prioritise the big infrastructure projects came after the recent Constitutional Court ruling that the 2-trillion-baht borrowing bill to finance infrastructure development was unconstitutional.
The ministry has had to turn to the annual budget, borrowing under the public debt law, public-private partnership (PPP) and infrastructure funds. With limited funds, setting priorities has become crucial.
Under the public debt law, state agencies can borrow in baht-denominated loans or bonds worth up to 20% of annual budget expenditure that year or in foreign currency at up to 10% of the budget expenditure.
Ms Chularat is confident that the ministry will be able to keep the country's public debt under its sustainable framework, stipulating that the debt does not exceed 60% of gross domestic product (GDP), though the four sources for funding have been implemented.
Public debt at the end of January edged up to 45.75% of GDP from 45.71% at the end of December and 45.34% at the end of November.
The huge investment required for the infrastructure developments and hefty financial burden to fund populist policies including the rice-pledging scheme have stoked fears that the country's public debt will outpace the Finance Ministry's threshold in coming years and this could pose a threat to the country's credit rating.
"We have yet to go into detail, we have only agreed in principle how to proceed. The Transport Ministry, which takes responsibility for most of the infrastructure projects, will set a priority on which projects can go ahead in the 2015 fiscal year and their sources of funding. For instance, the ministry will allow the private sector to invest in rolling stock projects through PPPs," she said.
Chula Sukmanop, director-general of the Office of Transport and Traffic Policy and Planning, recently said construction of four-lane roads, improving highways, land expropriation for motorways, construction of the Bang Pa-in-Saraburi-Nakhon Ratchasima Motorway, dual-track railways and a port should be based on the fiscal budget, while mass-transit routes and some dual-track railways should rely on domestic and foreign borrowings.
He has also suggested the Transport Ministry include the dual-track railways, port and four-lane roads with a budget of 90 billion baht in the fiscal-2015 budget.