Health chiefs in south Wales have accused local councils of a "complete lack of action" over patient transfers, leading to operations being cancelled.
NHS officials say operations will have to be delayed
Cardiff and Vale NHS Trust said it expected 190 patients to be awaiting transfer to social care in September.
Trust chairman Simon Jones said the two local authorities were "burying their heads in the sand".
Cardiff Council said it was responsible for only a fraction of the patients. Vale council also denied the claim.
The trust said it anticipated 190 medically-fit patients would be waiting transfer this month - although it accepted this figure had not been independently audited.
Mr Jones said: "Yet again we have seen a rise in the number of people in our hospital beds who don't need to be. More elderly people will become more frail and more dependent.
"More people will be in parts of our hospitals that are not appropriate for their needs. More people will have their operations cancelled as a result of this."
"All this because there appears to be a complete lack of action by Cardiff and Vale local authorities to do what they are supposed to."
A Cardiff Council spokesman said the trust's "ill-judged" statement only confused a "complex and emotive issue".
"We are disappointed that the Cardiff and Vale NHS Trust continue to unfairly blame us for the whole of the ongoing problem of delayed discharges of care," he said.
"The unaudited figures for September show that of 135 delayed discharges of care in the Cardiff area, only 23 are attributable to social care - a fall from August's level - whilst 32 are attributable to the health trust - an increase from August's level."
Cardiff said the main reason for social care delays when discharging patients was the lack of suitable accommodation.
"We cannot send people to accommodation that doesn't exist," added the council spokesman.
Responding to Cardiff Council's statement, a Cardiff and Vale NHS Trust spokesperson said: ¿The trust fully acknowledges that not all delays are a direct result of the councils' actions and that the issues surrounding patients' delays can be very complicated.
"However, the councils have a responsibility to act when patients need social services support and too many medically-fit patients are being forced to wait too long for this support.
"It is not only patients with an immediate need for social care services who are affected by this situation.
"The knock-on effects impact on countless numbers of other patients whose access to a bed is blocked.¿
Vale of Glamorgan director of community services James Cawley denied there was a "lack of action" and said the issued could "only be resolved by councils, organisations and agencies across Cardiff and the Vale working in partnership".
The council said it was determined to improve support of "vulnerable people" and called on the Welsh Assembly Government to take a "serious look" at the money allocated to councils for this.
An assembly government spokesman said he was aware of the concerns expressed by the trust and that discussions were taking place.
He added: "Since 2004-05 the Welsh Assembly Government has each year provided an extra £20m to increase capacity to care for people at home and in the community.
"In addition the assembly's budget for 2006-07 provided an extra £45m funding to local authorities for a range of adult social care funding pressures."