It could take weeks, if not months, to recover the bodies of three people trapped under the collapsed Didcot power station, police said.
Thames Valley Constable Scott Chilton said the structure is still "unsafe" and they are seeking "specialist advice" on how to progress.
"It will take many weeks and, in reality, many months before we will be able to get access to those trapped," he said.
The building collapsed at 4pm last Tuesday while workers were preparing it for demolition, killing worker Mike Collings and trapping three others inside the rubble.
Investigations into the exact cause of the collapse are still ongoing.
Frustrated families of those missing since the power station collapse two weeks ago say they are heartbroken that rescue work has halted.
A biker group in the North East has paid tribute to 'Whitby' Mick Collings, who is thought to have died in the power station collapse.
One person has died and three others are still missing after a building collapsed at Didcot Power Station yesterday.