A Senate inquiry's heard about half the money poured into poker machines, comes from problem gamblers.
The Senate's Community Affairs Committee's considering two Family First bills to cut the rate of problem gambling in Australia.
The bills propose restricting poker machines to racetracks and casinos, fortnightly credit limits through a smart card and compulsory limits on ATM withdrawals.
Dr Charles Livingstone, a health science lecturer from Monash University, wants to limit poker machine revenue to only one quarter of an operator's income, with the rest coming from traditional hospitality and entertainment.
He's told the hearing his research shows the main reason problem gamblers stop playing the pokies is because they run out of available funds from cash machines.