The Transport Ministry will propose two Red Line electric railway extensions worth around 26.5 billion baht to the cabinet to stage bidding by this September.
Peraphon Thawornsupacharoen, deputy permanent secretary for transport, said both projects would be submitted to the Office of the National Economic and Social Development Board (NESDB) next month before being forwarded to the cabinet for consideration.
If approval is granted, bidding would take place between July and September.
The two proposed Red Line extensions are a Taling Chan-Salaya line worth 19 billion baht and a Rangsit-Thammasat line costing 7.5 billion baht.
Mr Peraphon was speaking after the proposals were sent back to the ministry after being earlier forwarded to the NESDB.
The board demanded the ministry review all management and operation plans for the extensions including expected costs, revenue and the estimated number of passengers each day.
The ministry has assigned the State Railway of Thailand (SRT), which will run the Red Line, to work on the issues raised by the board and submit its conclusions within two weeks.
The projects will then be forwarded to the board again, he said.
Regarding investment plans for the two extensions, Mr Peraphon said the government would invest in infrastructure while the operating systems would be commissioned with the SRT's affiliated company which was in the process of being founded.
The SRT has voiced concerns over a delay in establishing the company, which could affect the launch of the Red Line.
The agency was in the process of hiring Chulalongkorn University to conduct a study on establishing the firm which should not take a long time, Mr Peraphon said.
The university's recommendations would subsequently be proposed to the SRT board, the NESDB and the cabinet for approval.
The agency, however, said it was not certain the affiliated firm would be established this year as it takes time to work out the organisation's structure and to recruit personnel.