The Oregon Medical Association is warning doctors to make sure people who ask for assisted suicide actually live in the state.

The association is responding to the possibility of people crossing the border from Idaho to take advantage of Oregon's new law allowing doctor-assisted suicide.Oregon is the only state in the nation that allows doctors to help terminally ill patients die. But the assisted-suicide law, which took effect 11 days ago, requires patients to be Oregon residents.

The state has no time requirement for people to establish residency.

The Oregon Medical Association wants doctors to require a driver's license and voter registration card to show a person lives in the state, spokesman Jim Kronenberg said.

"There is some measure of concern," he said. "It's kind of up to the doctor to decide if they are a bona fide resident or not."

Even if doctors follow the medical association's advice, a person could obtain a driver's license and voter registration card in a minimum of 21 days.

"That's certainly one of the arguments that has been posed against the law: that Oregon would have physician-assisted suicide mills," Kronenberg said.

Oregon residency can be shown with pay stubs, a rental contract or mailing address, said Michelle Davies, information services manager for the Salem Chamber of Commerce. "It's really easy to be a resident."

Under the Oregon law, two doctors must diagnose a patient as having a terminal illness that will result in death within six months, and another physician, who agrees to administer the drugs, must wait 15 days before prescribing them for the patient.