Deputy Prime Minister Prawit Wongsuwon has been spotted wearing another luxury watch, adding to questions over the government's "big brother" asset scandal.

A photo of Gen Prawit wearing another expensive watch was shared online after the Facebook page CSI LA posted the image on its page. It is said to be a Rolex Cosmograph Daytona Ice Blue Dial Platinum men's watch, worth between 1.9 and 2.4 million baht.

It was reported that the photo, which originally appeared on Matichon Weekly Online, was taken on Feb 14 when Gen Prawit was giving an interview at the Defence Ministry.

On Friday, political activist Srisuwan Janya petitioned the National Anti-Corruption Commission (NACC) to examine more evidence in connection with Gen Prawit's possession of a second Richard Mille watch.

His move came after a photo of Gen Prawit wearing the watch went viral on social media. The CSI LA page believes the watch to be an RM 30 model which costs about 4 million baht.

It is not the same one the deputy premier was seen wearing while raising his right hand to shield his face from the sun during a group photo session of new cabinet ministers on Dec 4.

The watch and the ring he wore that day raised questions over how he had come to acquire them and whether he had included them in his previous asset declarations as required by the NACC.

Gen Prawit, who is a "big brother" of military ministers in the government, was said to be stressed over the issue.

According to a close aide who asked not to be named, the general feels under pressure as he does not know how to make the public believe the Richard Mille watches belonged to a friend who died earlier this year, the source said. Gen Prawit and the friend had attended the same elementary school and had had a close relationship "like brothers" for more than 60 years.

The friend was a businessman and a watch lover who always lent Gen Prawit his watches. Some watches were not returned after his friend died, the source said.

The NACC has ordered Gen Prawit to clarify the source of the first Richard Mille within 30 days.