Thai police have arrested an alleged kingpin in Asia's illegal trade in endangered species, dealing a blow to a family-run syndicate that smuggles elephant ivory, rhino horn and tiger parts to Chinese and Vietnamese dealers.

Boonchai Bach, a Vietnamese national with Thai citizenship, was arrested yesterday evening over the smuggling of 14 rhino horns worth around $1 million from Africa to Thailand.

His downfall follows the 12 December arrest of Nikorn Wongprachan, a Thai National Parks and Wildlife Conservation official, at Bangkok's main airport as he attempted to smuggle the rhino horn from the quarantine section to a nearby apartment.

The horn was smuggled into Bangkok by a Chinese man who was arrested a day before on arrival from South Africa.

The police sting led to 40-year-old Boonchai, who financed the network.

"This is a major smuggling syndicate and Boonchai is a ringleader," police said after the suspect arrived at Suvarnabhumi airport ahead of his remand.

"Boonchai admitted he was involved," they said, adding he faces up to four years in jail for smuggling parts of protected animals.

For years Boonchai and the Bach family are believed to have operated with impunity from the town of Nakhon Phanom in northeast Thailand, bordering Laos.

The town is a pivot point in Asia's wildlife trafficking chain, in part because it is the narrowest neck of land for smuggled goods to transit through Thailand, into Laos and onto Vietnam, a major market for animal parts used in traditional medicine.

Freeland, a counter-trafficking organisation which works closely with Thai police, said the Bach family are part of a sprawling Southeast Asian crime organisation dubbed "Hydra".

The Bachs have "long run the international supply chain of illicit wildlife from Asia and Africa to major dealers in Laos, Vietnam and China," Freeland said in statement following the announcement of Boonchai's arrest.