The Thai government has closed ranks around its deputy minister of agriculture after an Australian newspaper reported that he served a jail sentence in that country for his role in a drug trafficking operation.

The Sydney Morning Herald reported Monday that Thammanat Prompao, who was appointed deputy minister in July, served four years in a Sydney jail in the 1990s for his role in an operation to smuggle more than 3 kilograms of heroin into Australia from Thailand.