BANGKOK - Authorities have found another 21 surrogate babies at the same condominium where they had earlier discovered nine surrogate babies with the same Japanese father.

The babies found at The Niche ID condo include 12 boys and nine girls aged between four months and about 10 months old, Thai PBS reported on Friday.

They were found in a unit at the condo near where the earlier group of babies were discovered.

The report quoted authorities as saying all the surrogate babies in the latest find have foreign parents - Western and Japanese nationals - as shown by the family names of the babies in the household registration document which has Mr Samran, a 41-year-old man, as the owner.

But it was not known how many of the babies have the same father, said Thai PBS. It also quoted authorities as saying most of the babies look Western, with a few looking Japanese.

Police are tracking down Mr Samran for questioning, said the report.

According to Channel 3, the 21 babies include triplets and twins.

Thai police launched a human trafficking probe after a Japanese man, believed to be the father of the nine babies found earlier at the condo, left the country. AFP reported that a Thai lawyer present during the raid told police the babies were fathered by an unnamed wealthy Japanese man. The infants are believed to be aged between two weeks and two years, although no official documents were found with them.

The babies had a nanny each to take care of them, AFP reported. The nannies said they were paid US$310 (S$388) a month to look after the infants.