PM's Office permanent secretary ML Panadda Diskul, said yesterday Government House has not undergone major improvements for years and that work on the compound was long overdue.
"There have not been any renovations for decades," he said.
The money will be spent on renovating buildings including the Naree Samosorn Building and Ban Phitsanulok.
After refurbishment, Ban Phitsanulok will serve as a work station for the future prime minister's advisory team. The renovation work will be handled by the military.
The press centre will also be improved to better accommodate the press, according to ML Panadda.
However, only small changes will be made to the Thai Khu Fah Building, he said. Major changes require permission from the Fine Arts Department because the building is registered as a historical site.
A Government House source said a reporters' room, known as Rang Nok Krajok, will be relocated from the Naree Samosorn Building to a new location close to the compound entrance.
"The prime minister's office in the Thai Khu Fah Building will receive some minor work," the source said.
Government House was reopened recently after having been closed since last year during the People’s Democratic Reform Committee protests against the Yingluck Shinawatra government.
ML Panadda yesterday presided over a religious ceremony attended by senior officials to bless Government House. The highlight was paying respects to a Brahma statue, a sacred figure.
The statue, located on the roof, is believed to ward off bad spirits and bring good fortune to those in power.
National Council for Peace and Order (NCPO) chief Gen Prayuth Chan-ocha did not attend the ceremony. He declined ML Panadda's invitation.
Political observers are taking a special interest in when or if Gen Prayuth will finally set foot in Government House, either in his present capacity or as a future premier.
Deputy army spokesman Wirachon Sukhonthapatiphak recently announced that Gen Prayuth would not use Government House as a workplace, but would continue working from the army headquarters on Ratchadamnoen Nok Avenue.
"It is not time for Gen Prayuth to set foot inside Government House. He said he would work at army headquarters. He won't come to Government House unless he assumes the premiership," the source said.
Gen Prayuth also turned down an invitation to attend a Muslim function at Government House today, and asked NCPO deputy chief Adul Saengsingkaew to attend instead, the source added.