Retailers selling lottery tickets for more than the face value can face fines of Bt10,000, according to the amended Government Lottery Office Act.
Before 2015, Bt80 tickets were often sold for Bt100 so the junta introduced one-month jail terms or Bt10,000 fines for those responsible.
The original 1974 act imposed up to Bt2,000 fines.
Anyone selling tickets at schools or to under-20s also faces a Bt10,000 fine.
The new law also improves the lottery office's internal structure and the allocation of profits while ensuring access for people with disabilities to lottery ticket retailers.