The woman, believed to be in her 80s or 90s, was picked up by a driver on Brandenburg Road in Mooloolah Valley on September 8 and dropped outside Nambour Hospital.

Police Inspector Matt Robinson says the woman was in a vulnerable situation and "very frail", requiring medical treatment.

However, he says police are not investigating any criminality or elderly abuse and just want to find her family.

"Our primary investigation is just to locate who this lady is to reunite her with her family," Insp Robinson.

Police have been unable to ask the woman who she is because she has been suffering a "challenging health situation", although she is improving after being transferred to Sunshine Coast University Hospital.

Insp Robinson said she was now able to communicate verbally and have conversations with people.

"It's not something where we've been able to go charging in very quickly with and we're taking it one step at a time and exploring those avenues as she's capable," he said.

Officers have put out a call for public assistance after trying many lines of inquiry, hoping it will help solve the mystery.

Police are unable to DNA test people without their permission, so they're hoping someone can identify the woman.

"That's going to be our quickest line of inquiry without bureaucracy, sending off inquiries that could take days to get back," Insp Robinson said.

"It only takes one person, who knows a person, to make one phone call and we can identify the lady."

He said the woman's situation was unique, agreeing that it was almost like a reverse missing person's case.

"We have the located person, we're just trying to find the family," he said.

Australian Associated Press