Udine prosecutor Andrea Gondolo told The Associated Press on Tuesday that his office has been unable to contact the athletes to ask whether they want to observe the testing of substances sequestered during a police raid in July on their training base in northern Italy.
The athletes can observe the testing themselves or designate a lawyer to do so. They have 20 days to respond once contacted.
"The problem has been finding an address to deliver the notification to see if they want to observe the tests, because some of the tests cannot be repeated," Gondolo said. "But I think we should be able to move forward within a month."
If the athletes cannot be contacted, prosecutors could go to the Jamaica Athletics Administrative Association instead.
The Canadian trainer, Christopher Xuereb, was already contacted.
Milton Samuda, a Jamaican attorney who represents Powell and Simpson, did not respond to emails or calls seeking comment.
Following the July hotel raid in Lignano Sabbiadoro, where the Jamaicans have been training for years, the athletes and Xuereb were formally placed under criminal investigation for violating Italy's doping laws.
The raid came after it was announced that Powell and Simpson had tested positive for the banned stimulant oxilofrine at the Jamaican championships in June.
The athletes blamed Xuereb, their newly hired trainer, and said that new supplements he provided caused the positive tests. Xuereb responded by saying that he didn't give the sprinters performance-enhancing drugs and suggested he was being made a scapegoat.
Italy's doping laws include sections for use, administration of banned substances and importation of banned substances.
Administration and importation carry more severe sentences and therefore Xuereb risks harsher punishment, Gondolo said, adding that the athletes do not risk prison time.
The confiscated substances appear to be from the United States, according to the containers they were found in, Gondolo said.
Powell and Simpson also risk bans from sports authorities. They have already stopped competing and missed last month's world championships in Moscow.
Associated Press reporter David McFadden in Kingston, Jamaica, contributed to this report.