The Public Sector Anti-Corruption Commission (PACC) plans to set up panels to look into irregularities involving funds for the destitute in two more provinces -- Bung Kan and Nong Khai.
The move comes after it found enough grounds to believe that funds earmarked for the underprivileged in both provinces were embezzled.
Committees have already been set up to look into alleged plundering of funds in Khon Kaen and Chiang Mai.
Acting PACC secretary-general Lt Col Kornthip Daroj said Thursday his agency will soon widen similar probes in eight other provinces -- Saraburi, Udon Thani, Surat Thani, Ayutthaya, Nan, Krabi, Trat and Trang.
A recent PACC probe found the names of people who died three years ago listed as eligible recipients at the welfare centre in Udon Thani.
In Krabi, at least 16 underprivileged and HIV patients did not receive any welfare money or only collected 1,000 baht instead of the 3,000 baht they were entitled to from the welfare centre there.
Lt Col Kornthip said initial scrutiny in all 12 provinces showed a similar practice -- funds earmarked for the underprivileged were disbursed, but the money did not go to those entitled to it.
"We are also investigating if there is a network behind this. If senior state officials are implicated, they will face a probe by the National Anti-Corruption Commission," Lt Col Kornthip said.
The committees have 90 days, until May 30, to complete their investigation which will be joined by the Anti-Money Laundering Office, he said, adding the probe will focus on the 2017 fiscal year for now.
The embezzlement scandal was first reported at the Khon Kaen Protection for the Destitute centre -- an agency that helps the underprivileged and HIV patients under the supervision of the Ministry of Social Development and Human Security.
Panida Yotpanya, 22, a social science student at Maha Sarakham University, and three friends working as interns at the agency lodged a complaint with the National Council for Peace and Order.
The students claimed they were ordered by centre director Phuangphayom Chitkhom and other senior officials to fill in forms and sign receipts for 2,000 villagers, worth nearly 7 million baht.