Army chief Udomdej Sitabutr warned Suthep Thaugsuban on Wednesday to avoid making political comments when he makes his first public statement on Thursday after leaving the monkhood.
Gen Udomdej advised the former leader of the People's Democratic Reform Committee to be cautious when speaking at a press conference planned by the PDRC foundation on Thursday.
He reminded the former veteran politician and street protest leader he would be allowed no privileges if he steps over the line.
The army commander is also secretary-general of the National Council for Peace and Order (NCPO).
"I would like all parties to be cautious when they speak, because the NCPO enforces all rules with the same standard,'' he said. ''I would like him to think about the stability of the country.''
Mr Suthep will outline plans for the foundation set up in December last year to campaign for national reforms. He chairs the foundation with 11 others who rallied with him before the coup in May last year under the PDRC banner to oust the Pheu Thai Party government of then-prime minister Yingluck Shinawatra.
The former Democrat Party veteran on Tuesday left the temple in Surat Thani where he was ordained after the May 22 coup last year. He plans to introduce the line-up of executive members of the foundation on Thursday.
Akanat Promphan, the foundation's secretary-general, said the foundation has no intention to renew political conflicts, and promised no disruption of the junta's reform campaign.
The foundation ''will push for reform in a constructive manner for the public benefit. There will be no conditions which could lead to political conflict, and no obstruction to the progress of the reform plan carried out by the National Council for Peace and Order," Mr Akanat wrote on his Facebook account on Wednesday.
The venue for the media conference on Thursday will be closely observed by soldiers sent by the NCPO, to ensure speakers do not defy the order banning political gatherings by more than five people.