All 14 AS350 remaining six-seater helicopters operated by the Natural Resources and Environment Ministry have been grounded for safety check after one crashed on Tuesday morning, Natural Resources and Environment Minister Suwit Khunkitti said on Thursday.
Mr Suwit said the AS350s, which were built and certificated in the United States, would not be allowed back in the air until they had been thoroughly checked.
The minister admitted that some parts of the helicopters have been recycled for use.
The air force is in charge of determining the cause of crash, Mr Suwit said. He believed a fact-finding committee woud be set up to investigate.
The ill-fated helicopter took off from an air base in Phitsanulok about 7.30am on Tuesday destined for Phu Phayak mountain in Nan's Chalerm Prakiat district, where three senior state officials were due to preside over a ceremony for a reforestration project.
The helicopter took off in heavy rain, lost contact with the air base and disappeared from the radar about 30 minutes later.
All five people aboard - three state officials, the pilot and flight engineer - were killed in the crash.
The ministry has 14 remaining AS350 helicopters, but only 12 are rated airworthy.