Nithinon Srithaniyanan, 25, was arrested at the Thai-Laotian Friendship Bridge checkpoint in Nong Khai’s Muang district at 9am.

Customs officials searched Nithinon and found the tubes containing semen after they have spotted the man crossing the border several times carrying a large bag.

The man admitted that he had carried frozen semen tubes to a clinic in Laos 12 times and to a hospital and a clinic in Cambodia 13 times since last year. Each time he was paid Bt5,000.

Following the arrest, he was interrogated by Nimit Saeng-amphai, customs chief at the checkpoint, and Dr Chatchawal Ritthiti, deputy chief public health officer for Nong Khai.

The man produced doctors’ certificates saying the semen tubes belonged to Chinese and Vietnamese men but the authorities still arrested him for violating the technology-assisted fertilisation act that bans the export of human sperm, eggs and foetuses.

Nimit said customs officials had been monitoring Nithinon after he was spotted carrying a large bag while crossing the border at the Aranyaprathet checkpoint to Cambodia and the Nong Khai checkpoint to Laos.

The arrest was made on a tips-off that Nithinon would cross the border again yesterday morning.

Nithinon said he had hired by a half Thai-Japanese man, identified only as “Yu”.

Nimit said the selling of sperm and eggs or foetus was immoral and it was the first time that such an arrest was made.

Chatchawal said a lab test would later be performed on the seized tubes.

From an initial observation, it was believed that the semen would be used for in vitro fertilisation at a clinic, Chatchawal said. He said Thai doctors might cross the border to perform the fertilisation procedure.