Cabinet members in the first and second Thaksin governments will be probed for evidence of corruption, illegal activity and being unusually rich, Alongkorn said.

The probe will begin with Thaksin. It will examine tax exemptions for businesses once controlled by his family, including Shin Satellite and AIS. It will also probe the cut in royalty fees for the iTV station following its move into Shinawatra hands.

Thaksin will also be investigated for amendments that raised the foreign-ownership ceiling in Thai companies, allegedly negotiating on behalf of his family's business during the Apec summit in Mexico and allegedly turning the privatisation of state enterprises into a Shinawatra-enrichment plan.

PM's Office Minister Newin Chidchob faces a probe over alleged corruption in a rubber-sampling bidding project worth Bt1.4 billion. Agriculture Minister Khunying Sudarat Keyuraphan will be probed for possible legal violations in the bidding for Bt900 million worth of computers for the Health Ministry and the bidding for a drainage system at Suvarnabhumi Airport.

Thai Rak Thai deputy leader Bhokin Balakula faces a probe over alleged collusion related to a bid for fire engines at the Interior Ministry.