A bet by a child (under 18) or by an adult with a child is an offence under the Lottery and Gaming Act 1936 (SA) [ss 53, 54]. It is also an offence to receive money from a child for the purpose of gambling [s 55].
Children cannot operate poker machines or enter areas where poker machines are operating [Gaming Machines Act 1992 (SA) ss 56-58]. Similar restrictions apply to 'Keno' games in licensed premises.
It is also an offence to sell lottery tickets to children under the age of 18 years, State Lotteries Act 1966 (SA) [s 17B]. However, it is a defence if the ticket seller reasonably believed the child was over 18 years.
See also Cheating at Gambling.