BANGKOK (THE NATION/ASIA NEWS NETWORK) - Thai police are awaiting the return of a Japanese man at the centre of surrogacy allegations concerning many children, whose lawyer has said will go back to Thailand this week to give information.

Deputy Metropolitan police commissioner Pol Maj Gen Thitirat Nongharnpitak said Mitsutoki Shigeta's lawyer told police that his client may meet police between Monday and Wednesday.

However, there has been no confirmation yet from his side about the meeting.

Thitirat said police wished to ask Shigeta his real intention and the reason why he wanted to father as many children as possible via surrogacy.

"We would like to know about the babies whom Shigeta took out of Thailand and whether they are well-treated or face any threats," he said.

Thai authorities said the 24-year-old Japanese had fathered tens of babies through Thai surrogate mothers. He has not yet been charged with any crime.

Police will send a team to Cambodia to check reports that the Japanese man took four babies to Phnom Penh and raised them there.

A police source said if Shigeta failed to meet Thai police, a team would be set up to monitor people who were close to him, such as Samran Pasanay, owner of a house where the surrogate mothers and babies stayed, as well as Dr Pisit Tantiwattanakul, owner of a fertility clinic in Lumpini district that allegedly performed surrogacy services for the Japanese.

Meanwhile, police will issue a summons for Dr Pisit, possibly on Monday, to discuss Shigeta and the doctor had until Friday to report himself, said Pol Maj Gen Suebsak Punsura, a Metropolitan police commander.

The Public Health Ministry last week sought police action against Dr Pisit for being negligent and allowing medical offences in his clinic. Pol Col Chaiya Kongsub, chief of Lumpini police, said the doctor was likely to still be here as the punishment was light - up to one year in prison or a fine of not more than 20,000 baht (S$781) or both, he said.

Meanwhile, an Australian same-sex couple have been permitted to leave Thailand with a surrogate baby after background checks by Thai immigration authorities.

The couple sought assistance from the Australian embassy in Bangkok on Friday after being stopped at the airport. Four Australian and American couples were prevented from leaving the Kingdom with children born from Thai surrogate mothers last Thursday.

ABC News Radio confirmed one of the couples arrived in Singapore with twins born last month via a surrogate.