He was responding to the low turnout of NRC applicants.
As of Aug 18, the fifth day of the application, 472 people were nominated — 126 nominated by juristic persons and 346 from the provinces.
The applications can be submitted until Sept 2.
Gen Surasak Karnchanarat, defence permanent secretary, dismissed views that the low number indicated people were not interested in national reform.
The causes of the lacklustre interest are said to be the asset declaration requirement for NRC members and rumours of rigged competition, especially in the provinces, according to Thai media.
Gen Surasak dismissed the speculation, saying it was too soon to tell and urged all to wait for the final count on the last day.
Two types of screening panels were set up to shortlist NRC candidates.
The first type comprises 11 seven-member committees, one for each area to be reformed, all appointed by the NCPO.
The 11 areas to be reformed are: politics, public administration, laws and judicial process, local administration, education, economy, energy, public health and environment, mass media, social affairs and others.
The 11 committees will each shortlist up to 50 candidates to be proposed by non-profit organisations.
The other type is the provincial screening committees, one for each of the 76 provinces and Bangkok.
The 76 provincial selection committees comprises the governor, chief judge of the provincial court, chairman of the provincial administration organisation, representatives of the community organisation councils at the provincial level and chairman of the provincial election commission.
For Bangkok, the selection committee consists of the president of the Council of University Presidents of Thailand, chief justice of the Civil Court, Bangkok Metropolitan Administration permanent secretary and chairman of the Bangkok election commission.
The provincial and Bangkok screening committees will each choose five candidates who are local people in their respective areas.
The NCPO will then pick one NRC member for each of the provincial and Bangkok lists and any number it sees fit from the reform-area lists but not more than 250 total.