No trace of missing Bribie grandmother

Bribie Island police are dispelling rumours that a grandmother missing for nearly a week has already been found, fearing residents may relax their efforts to find her.

Marian Wallace, 71, left the Embracia nursing facility at Bongaree around 3pm (AEST) on September 7 and was last seen at a nearby intersection.

Police and Mrs Wallace's family hold growing concerns for her safety as she suffers from dementia and is likely to be in a confused state.

Senior Constable Chris Bird says police have now doorknocked every home on the island.

"To date nothing has been located and as of now virtually the whole island has been searched to some degree," he told AAP.

News of Mrs Wallace's disappearance was spread through flyers and social media.

"The response we've had from the public has been enormous," Sen Const Bird said.

"Even though they don't know her, everyone knows that there's an elderly population on Bribie and this could happen to anybody."

The relentless search has now drawn in the SES, water police, helicopters, the dog squad, police divers and wildlife rangers.

But one thing working against the significant operation is a rumour that Mrs Wallace has already been found.

Sen Const Bird said police were eager to shut down the rumour and encourage residents to continue checking their properties for Mrs Wallace.

A spokeswoman for the Embracia nursing facility confirmed to AAP that Mrs Wallace had been a resident prior to her disappearance.

The facility was putting all of its resources into assisting police with the search and helping the family, the spokeswoman said.

Mrs Wallace would have experienced mild weather conditions during the week if she had been outside, Sen Const Bird said.

He said officers were constantly receiving new information and urged anyone who may have seen Mrs Wallace to contact police.

"We investigate each and every piece of information we get. Hopefully we'll get the right piece of information that will lead us straight to her."

Mrs Wallace was last seen wearing an aqua green coloured jacket, light blue jeans and black shoes.

She was wearing glasses and may have also been carrying a black handbag.