Plans to ask care home owners to take residents with Covid-19 have been described as "alarming".
Durham County Council has asked providers for "expressions of interest" in setting up isolation units to keep older people out of hospital.
The county has the second highest number of care home Covid-19 deaths in England and opposition councillors said the policy would put residents at risk.
The Labour-run council said it was complying with government instructions.
Independent councillor Paul Sexton, whose mother died with coronavirus in a care home, questioned why residents had been discharged from hospitals earlier in the pandemic when there were free beds and the local Nightingale hospital was not in use.
Doing it again suggested older people were considered "expendable", he said.
"Unless they're separate buildings and you have no staff going between, the virus will spread," he said.
"We've had months to look at a different alternative."
Liberal Democrat councillors said the authority had interpreted a request to find alternative beds for Covid-positive patients as a suggestion they be put into care homes.
Group leader Amanda Hopgood said providers were "alarmed at what was being proposed".
The local authority said councils had been instructed by the Department for Health and Social Care (DHSC) to "indentify accommodation" as part of their social care winter plans.
It was contacting care homes before considering its position and responding to the government, it said.
The DHSC said it was providing £588m for designated accommodation.
No home would be forced to admit Covid-positive residents and local authorities would remain responsible for providing alternative accommodation, it said.
Office for National Statistics figures show 364 people died in County Durham care homes between 10 April and 16 October.
In July the council was criticised for allowing residents with coronavirus to be returned to care homes.