The Election Commission on Tuesday removed Puchong Nutrawong as its secretary-general for poor performance.
Tanith Sriprateth, an executive of the Office of the Election Commission, said that the EC decided by a 4-1 vote that Mr Puchong had failed to satisfy four criteria on his performance evaluation.
He failed to implement the EC's annual action plan, failed to follow through on EC resolutions, came up short in good governance, and did not meet requirements for organisational improvement.
The EC earlier had its sub-committee evaluate the performance of Mr Puchong. The panel reported its findings on Dec 1, Mr Tanith said.
"The sub-committee gave quite low scores on some criteria. Although the EC raised the scores, the total scores did not reach the 60% threshold. So the EC resolved to terminate his employment effective today," Mr Tanith said on Tuesday.
Boonyakiat Rakchartcharoen, the senior-most deputy EC secretary-general, was named acting secretary-general and the EC will search for a permanent successor as soon as possible, he said.
Regarding performance on organisational improvement, Mr Tanith said that Mr Puchong had set several goals, but failed to complete them on schedule.
The tasks included the EC office's reorganisation and the establishment of the EC's information-technology centre and anti-graft intelligence centre.
A source said the EC previously had asked Mr Puchong how he would improve his performance but he asked the EC to decide his fate immediately.
Mr Puchong, 63, did not attend the meeting, taking sick leave after saying he fell down the stairs and injured his arm.