Pol Gen Pongsapat was given the dual posts during the previous Yingluck Shinawatra government. He is replaced by his deputy Permpong Chaovalit, 59.
In the 84th announcement broadcast live on Thursday night, the National Council for Peace and Order relieved Pol Gen Pongsapat of the ONCB top post. But he will remain as deputy national police chief.
Earlier, a spokesperson for the NCPO denied the sacking.
Col Sirichan Ngathong said a document posted on the social media on Wednesday and detailing Pol Gen Pongsapat's removal from office to become PM's office adviser, was a forgery.
Mr Suchart, the chief of the Corrections Department, is now made inspector-general.