Thai Finance Minister Chalongphob Sussangkarn says he is mystified by Thaksin's latest venture, but has promised to uncover the truth.
"This money which would be used for Manchester City is still a mystery to Thailand, so I cannot tell where the money will be coming from," he said on the sidelines of the World Economic Forum on East Asia conference in Singapore.
"I am sure the Asset Examination Commission will look at the source of these funds and try to see whether they are legal funds that were taken out or by other means.
"If the deal goes ahead and the money is paid they will try to look at it.
"We don't know yet how he is going to finance it. We won't know until the deal is finalised."