The government is adopting double standards in its probe of Deputy Prime Minister Prawit Wongsuwon's assets, says Pheu Thai Party's acting deputy spokesman Anusorn Iamsa-ard.
Mr Anusorn said Monday the public are waiting to hear from Gen Prawit about his possession of luxury trinkets.
The more Gen Prawit keeps quiet, the more it will hurt the government's image, Mr Anurson said.
He said investigations against government's opponents are always carried out rapidly while probes into those in the government tend to proceed slowly.
"If it were politicians, they would have been summoned for several rounds of questioning. But when it comes to probing people of the same clique, there is no hurry," Mr Anusorn said.
Gen Prawit's high-priced trinkets have caught the attention of the National Anti-Corruption Commission (NACC) after he failed to report them in his declaration of assets and liabilities as required by law.
A Richard Mille watch and diamond ring came under the media spotlight when Gen Prawit raised his right hand while trying to shield his face from the sun during a group photo session for the new cabinet on Dec 4.
The NACC has ordered Gen Prawit to clarify the source of the Richard Mille within 30 days.
Gen Prawit was also spotted wearing another luxury watch recently. A photo of him wearing the watch was shared online after a Facebook user, CSI LA, posted the image on the page, saying it was likely a Rolex Cosmograph Daytona Ice Blue Dial Platinum men's watch which costs between 1.9-2.4 million baht.
The page administrator said a follower sent the photo to him. The price of the watch is about 1.9 million baht if it is bought through Amazon.com, he said. On Friday, political activist Srisuwan Janya petitioned the NACC, demanding the anti-graft agency gather more evidence in connection with Gen Prawit's possession of a second Richard Mille watch.
Separately, a National Legislative Assembly (NLA) committee, vetting an organic bill on national anti-corruption, is expected to table the bill in the assembly on Thursday, said Klanarong Chanthik, a member of the committee.
Among the bill's key proposals is a provision requiring political-office holders' spouses, who are not married legally and do not possess a marriage certificate, to declare their assets and liabilities, though Mr Klanarong admitted that it is difficult to define such spouses.
He said the NACC also investigates the assets of spouses who have divorced politicians or who live with politicians and whose assets are combined.