The National Human Rights Commission (NHRC) says it risks being downgraded if it fails to comply with international standards on the selection of its members.
The issue was discussed at the annual meeting of the International Co-ordinating Committee of National Human Rights Institutions (ICC) in Switzerland from March 11-13, according to the NHRC's summary report.
The report said the meeting discussed downgrading the NHRC from level A to B in October this year.
The downgrade will be carried out if Thailand fails to ensure the constitution complies with the Paris Principles governing the NHRC member selection process, the report said.
The Paris Principles are a set of international standards which guide the work of national human rights institutions.
The internationally agreed principles define the role, composition, status and functions of the agencies.
The new charter must enable civic groups to participate in the selection of the NHRC, said the report, amid concerns charter drafters are seeking to merge the NHRC with the Ombudsman's office.
The report said any merger would mean disbanding the NHRC.
If a new human rights body is to be set up under the new charter and the government wishes to be a signatory of the ICC, it must re-apply for membership of the body, the report said.
The new body must produce its first annual human rights assessment report before being qualified to apply for membership. The process could take three years.