BANGKOK—Thailand’s former Prime Minister Yingluck Shinawatra said Friday that she sees little difference between the current military government’s $1 billion-plus plan to support rice prices and the ill-fated subsidy program for which she could spend up to 10 years in prison.

“In principle, I think it’s not any different from [the earlier] rice program,” she told reporters at Bangkok’s court building, where she is on trial for allegedly mishandling the multibillion-dollar scheme. She denies any wrongdoing.

“The...