Mitsutoki Shigeta, a Japanese businessman, departs Thailand with one of the children he fathered. Mr Shigeta is believed to have fathered at least 15 babies delivered by Thai surrogate mothers before police busted him, took many of the babies to a government orphanage and he fled towards Cambodia. (File photo, via internet)

Three children believed to have been born to surrogate mothers hired by Japanese businessman Mitsutoki Shigeta, who earlier made headlines for allegedly fathering at least 13 surrogate babies in Thailand, have been found in Cambodia.

The Department of Special Investigation (DSI) mentioned the three children at a meeting Thursday of the National Legislative Assembly's (NLA) special committee studying measures to protect babies born with the help of medical fertility technologies and left by their surrogate parents after previous crackdowns.

None of the DSI's officials, however, have met the three children in person, said Methini Ratrasan, director of the DSI's Bureau of Technology and Information Inspection Centre.

The DSI conducted its own investigation which found the three children in Cambodia.

Their mothers are thought to be Thai, hired by Mr Shigeta as surrogates.

He is thought to have taken them there and left them there with caregivers.

Mr Shigeta allegedly hired surrogate mothers who, with the help of medical teams, gave birth to the 13 children involved in previous allegations.

An unnamed official representing the Social Development and Human Security Ministry at Thursday's meeting said the 13 surrogate children have been in the care of the ministry's child protection centre in Nonthaburi since the surrogacy scandal erupted.

The official assured all were in good health.

Mr Shigeta had petitioned for paternal rights over the children and four court hearings have been held in the case, said the source, adding the next hearing is scheduled for Wednesday.

Ms Methini also revealed one of the women found to have been hired to carry babies for Mr Shigeta had recently travelled to Cambodia where she has been hired by another individual as a surrogate mother.

The woman works with a surrogacy broker identified only as Mariam, according to Ms Methini.

Regarding 21 surrogate children found at another site in the Lat Phrao area of Bangkok, authorities were expanding the investigation to determine if they belonged to surrogate mothers hired by Mr Shigeta, NLA member Kitti Wasinon said.

The National Operation Centre on Prevention and Suppression of Human Trafficking and police have determined the 21 surrogate children weren't exploited for the stem cell trade as was initially suspected, Ms Methini said.

Authorities are seeking to determine if they are biologically related to Mr Shigeta.

Legal action had been taken against five medical institutions accused of providing illegal surrogacy services, said Akom Pradittasuwan, director of the Bureau of Sanatorium and Healing Arts.

Several medical professionals were now being investigated by the Medical Council of Thailand, Dr Akom said.

Most recently, a total of 30 couples have submitted applications for surrogacy services.

Of them, 23 have won approval by the national child protection committee, he said.