Thailand's move to investigate the export of 100 undocumented tigers to China is being praised by conservationists.

Surapon Duangkhae, secretary-general of Wildlife Fund Thailand, said the National Counter Corruption Commission investigation was critical in addressing a thriving illegal wildlife trade, the Bangkok Post said Saturday. Surapon blamed poor law enforcement for the lively trade.

"Investigators should find out where the tigers came from -- whether from Sri Racha Tiger Zoo in Chon Buri as claimed by the zoo owners -- or from natural forests," Surapon said.

He said the zoo owners did not produced documentation about the tigers' origins, which is required for export. Tigers can be traded, but the exchange must be government-to-government.

In the matter, a former forest department chief allegedly delivered tigers to China without approval from the National Wildlife Protection Committee. The Ministry of Natural Resources and Environment appointed an investigative committee, which concluded the former head committed no crime.