Detectives have been treating the disappearance of Lesley Trotter, 78, as a possible homicide.
On Tuesday they confirmed their focus had shifted to six commercial waste sites across Brisbane.
Investigators said last week they believed she was dead after conducting extensive searches at Brisbane's Mt Coot-tha, where Ms Trotter was known to bushwalk.
She last spoke to her family on March 27 and was not at her Toowong home when relatives visited the following day.
Her mobile phone and wallet were found in her unit and her car was still in the garage.
Detective Superintendent Andrew Massingham said police believe Ms Trotter's body was in a wheelie bin on Maryvale Street at Toowong on March 28 before rubbish trucks delivered its contents to a Nudgee transfer station.
"We have strong evidence to suggest that, evidence I'm very confident in," Supt Massingham told reporters.
Detectives couldn't rule out foul play and continued to treat the matter as suspicious.
An additional 22 trucks visited the site that day.
Their loads were compressed before being taken to six dump sites across Rochedale and Swanbank.
"The location of that rubbish at each of those sites has now been quarantined. In fact, it was quarantined over the weekend," Supt Massingham said.
"We are currently planning an extensive search of both those sites to recover the remains of the person we believe to be Lesley Trotter."
Supt Massingham indicated the search would be complex and difficult, with excavation needed at Rochedale.
Once engineers finalise the scale of area to comb, police will commence a "piece-by-piece" operation.
"These types of searches are not uncommon, but I think the scale of this one will make it quite complex," he added.
"It will require a combination of resources from many different specialised areas to ensure we leave no stone unturned."
Supt Massingham said it was important for police to not disclose information about Ms Trotter's body until they were able to "exhaust people's memory" with respect to their recollections of March 28.
He did not rule out links to a dispute over recycling in the area, with Ms Trotter well known in the neighbourhood for ensuring rubbish was put into the correct bins.
"It is a line of inquiry," he said.
"It's certainly an issue that has been raised by a number of people in respect to that behaviour and we can't rule out that that has something to do with her death in some way."
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