Thailand is a major transit hub for wildlife smugglers who often sell highly prized endangered animals and animal parts on the lucrative black market in Asia.

The arrests and seizures of ivory, valued at around $300,000 and smuggled by ship from Africa, occurred across seven provinces in Thailand on Thursday, anti-wildlife trafficking authorities said.

"It was the biggest lot we seized in 10 years," Patompong Thongchamroon, from the national police's environmental crime division, told AFP.

An officer discovered a private Facebook group selling smuggled African ivory in Thailand, Patompong said, adding that after months of investigating police had arrested nine Thais who were group administrators tasked with posting the ivory for sale.

The group were charged with illegal possession and trade of protected wildlife parts, which carries a maximum penalty of 10 years in prison, a million baht ($30,800) fine, or both, according to a police statement.

The ivory haul included cut pieces and fragments, as well as prayer beads, jewellery and knife handles, police said, adding that the target buyers were Thai and Vietnamese.

The Convention on International Trade in Endangered Species, or CITES, has officially banned the international trade of elephant ivory since 1990.

African elephants as well as Asian elephants -- Thailand's national animal -- are classified as endangered globally by the International Union for the Conservation of Nature.