Secretary-general Puchong Nutrawong said yesterday that the EC has also ordered its provincial offices to help governors prepare for the selection of provincial representatives.
Up to 250 NRC members would come from 77 provinces and the people hand-picked by the National Council for Peace and Order from those shortlisted by legal entities nationwide.
Governors will chair the selection committees for provincial representatives.
The other NRC members would be nominated for at least 11 groups working on various spheres of national reform.
Before candidate registration opens on Thursday, the EC would conduct a rehearsal of the system on Wednesday.