South Australian independent senator Nick Xenophon has called on the state government to shut down an outdoor poker machine area at the Adelaide Casino.
Senator Xenophon said the outdoor area was designed to get around South Australia's anti-smoking laws.
He said it showed how cynical the gaming industry was.
"They are so desperate to keep players gambling, they have moved machines outside so that smokers can avoid a break in play."
The senator said the state government should support a bill to be introduced to parliament by independent upper house MP John Darley which would make the outdoor poker machine area illegal.
He said while pubs and clubs were not allowed to move machines outdoors, the casino appeared to be operating under some sort of an exemption.
"The South Australian government needs to agree today to close this loophole and get these machines out of outdoor areas," Senator Xenophon said.
"Clubs and hotels are not allowed to do this and the casino should not be allowed to either."
The casino has 20 poker machines in its courtyard area which it calls The Oasis.
The SA government has ordered an investigation into the casino's move.
In a statement, Gambling Minister Bernard Finnigan said the poker machines in The Oasis had been disabled on Thursday after a visit from liquor and gambling inspectors.
Mr Finnigan said checks would continue to ensure the machines remained disabled.
The minister said the casino had asked for permission to operate gaming machines in the outdoor area about two years ago, but had been refused.
He said he was disappointed the casino had installed the machines anyway, given the government's smoke-free gaming policy.
"I am seeking further advice on the steps necessary to ensure casino gaming areas remain non-smoking," Mr Finnigan said.
"I am not aware of any other gaming venues where a patron can smoke next to or while playing a gaming machine."