Thailand now has 20 ministries.
Commenting on civil service reform in a TV programme, Visanu Krue-ngam, a NCPO adviser, said the NCPO raised the possibility a water ministry should be set up following the lessons of the great flood in 2011.
The various agencies responsible for water management now spread across several ministries could be consolidated into one, he said.
Another idea floated was for a rail transport ministry to deal with everything on rail, from dual-track and high-speed trains to electric mass transit, both above ground and underground.
It was felt the state should take the role of track management, from designing to setting construction standards, while the private sector could take over above-rail operations.
The Department of Investigation is another issue discussed as its role has now deviated far from its job description, he said.
The DSI is by design responsible for complex cases for which police may not have the expertise or readiness to handle, not for ordinary criminal cases. Over time, it had transferred too many cases, even the most ordinary ones, to its jurisdiction as "special cases".
This had prompted a rethink of its duties and existence.
"As for the Tourism and Sports Ministry, it might be necessary in another 10 years to put the two together, but today we need to review whether they belong in the same portfolio," Mr Visanu said.
A Matichon report said the units that may be consolidated into the new water ministry will likely be the royal irrigation, water resource and groundwater resources departments under the Agriculture ministry; the Water Quality Management Office and the Pollution Control Department under the Natural Resources and Environment Ministry; state enterprises under the Interior Ministry - the Metropolitan Water Authority, Provincial Water Authority and Public Works and Town and Country Planning Office - and the Waterway Development and Maintenance Centre under the Transport Ministry.