Mr Wiboon was speaking at a press briefing on the the National Council for Peace and Order (NCPO)'s 85th announcement which ordered the suspension of all local elections.
The announcement, made on Tuesday, said vacant local body seats will be filled via a selection process instead of by election.
Mr Wiboon said chief executives of local bodies who finish their terms will be replaced by chief administrators as caretaker leaders. Members of local bodies, meanwhile, will be appointed by selection committees.
He said Bangkok council members will be selected by panelists chosen by the interior permanent secretary, while panelists in other provinces will be chosen by provincial governors.
Mr Wiboon said the new method will not interfere with the work of local administrations, but was a necessary adjustment under the current political situation.
Critics saw the move as an attempt to stamp out the influence of national-level politicians in local administrations.
Others said the NCPO had no other choice, since the country is under martial law and political gatherings are banned.
Mr Wiboon said selection committee members will be people with credibility and would be readily accepted.
"Thailand needs reconciliation, and an election could lead to differences of opinion. It is not the time for polls to be held," Mr Wiboon said.
He brushed aside criticism that the Interior Ministry would grab power during the selection process, saying provincial governors will only have the authority to oversee the process and would not try to dominate it for their own ends.
The selection will be done by qualified panelists, who will not be commanded by the governors, in a process that can be monitored by locals, Mr Wiboon added.
Election Commission (EC) secretary-general Puchong Nutrawong said the agency believed the NCPO had considered the new move thoroughly.
The selection process is suitable because peace and order in the country is necessary before it can return to full electoral democracy, he said.
The EC will inform the chiefs of its 77 provincial offices who will join selection committees to be well prepared and actively support the process, he said.