MRTA governor Yongsit Rotsikun said the project could be built on top of a proposed maintenance centre for the Blue and Orange lines.
Under the plan, private companies, potentially hotels, convention centres, offices and retailers, would bid for a concession to develop the space.
"That will help make much bigger profits ... and when we have enough income, we won't have to rely on loans," Mr Yongsit said.
The maintenance centre is due to be constructed next to the MRTA's headquarters on Rama IX Road in Huai Khwang district.
The MRTA is in the process of hiring King Mongkut's Institute of Technology Ladkrabang to carry out a feasibility study for the plan, Mr Yongsit said.
It has been exploring this kind of project for more than a decade and hired a number of companies to study the possibility of constructing developments along its electric rail routes in 2001 and 2010.
The MRTA has also held discussions with the Industrial Estate Authority of Thailand about allowing light industries, such as jewellery-making businesses, to operate on its premises.
The Council of State has looked at the legal implications of the plans and ruled in favour of the MRTA's project at the maintenance centre, Mr Yongsit said.
The MRTA needs new sources of income to pay off about 100 billion baht in accumulated debt, he added.
Total revenues for the past decade have come to just 10 billion baht, leaving at least 90 billion baht to pay with no clear income sources.
One previous study showed the Blue Line, which runs between Hua Lamphong and Bang Sue, needs to carry about 800,000 passengers each day to break even. The service currently attracts only 300,000 passengers a day.
In June, the MRTA sought permission to hike subway fares.
The Orange Line between Taling Chan and Min Buri is still in the planning stage. It is scheduled to be completed by 2019.