The feasibility study on the 19-kilometre motorway between Srinakarin and Suvarnabhumi International Airport will take six months, and public hearings on the project will be held while the EIA is being conducted, the officials added.
The EIA and public hearings will take an additional six months, and the entire process is expected to be completed next year, they said.
If the Cabinet approves the project, it could start immediately because all of its construction areas are under the supervision of the government, officials said.
The Expressway Authority of Thailand is developing a strategy to attract private investment into a public-private partnership for the highway, officials said, cautioning, however, that they had not finalised an investment model for the project.
Local media reports have said it is attempting to get Airports of Thailand Plc (AOT) to invest in the project.
Kirati Kitmanawat, deputy director of AOT, downplayed the reports, saying no formal talks with the Expressway Authority of Thailand had taken place.
AOT, which supervises six airports in Thailand, is a state-owned company. The Ministry of Finance holds a 70% stake in it.
The proposed motorway will start at Srinakarin Interchange and end at Lat Krabang. Its estimated cost is 21.89 billion baht.