The case has caused controversy in both Thailand and Australia, bringing calls to prohibit commercial surrogacy in the Southeast Asian country to end a lucrative trade.
In Australia, the case has sparked calls for an overhaul of surrogacy laws to cut the number of couples travelling abroad to find surrogates.
The nationwide inspection in Thailand would start next week, Lieutenant Colonel Chatmongkol Wasinamorn of the police consumer protection division said yesterday.
Commercial surrogacy is against the Medical Council of Thailand's code of conduct. Surrogacy is permitted if blood relatives are the surrogates, although exceptions are permitted.
The surrogate mother, Pattaramon Janbua, 21, has said she agreed to a fee of 350,000 baht (£6,500) to carry the twins for the Australian couple.