The State Opposition says it will decide this week whether to refer dealings between the Health Minister Kim Hames and the troubled Peel Health Campus to the state's corruption watchdog.
Dr Hames has admitted seeking a donation from the Peel Health Campus for the Mandurah sailing club, where he used to be a member.
He is being backed by the Premier Colin Barnett, who insists he has done nothing wrong.
But Labor's health spokesman Roger Cook says it is a clear conflict of interest.
"The minister for health was seeking a donation to his private yacht club while at the same time he was in serious consideration on a very important and large commercial contract for the private operator of the Peel Health Campus," he said.
"The hospital is already being investigated over claims it made tens of thousands of dollars through a scheme that awarded doctors cash bonuses for admitting patients.
"That seems to me to be a point-blank prima-facie case of a conflict of interest and it seems to me that there are very real issues now, of potential corruption that must be fully investigated by the CCC," (Corruption and Crime Commission).
However, the Health Minister Kim Hames says the move smacks of desperation.
Dr Hames says there are many holes in the opposition's case.
"To be successful in prosecuting a claim like that they'd need me to have made the application, which didn't happen, me to have got the money that didn't happen, the yacht club to be in my electorate which it isn't," he said.
He says taking the matter to the Corruption and Crime Commission is a joke.
"This is supposed to be a body to deal with serious crime and corruption."