Owen Mor nursing home on the Culmore Road remains closed to new admissions weeks after the health regulator, the RQIA, obtained a court order.
Management of the home has apologised for the treatment of those in its care.
Older People commissioner Eddie Lynch said he could not rule out ordering an inquiry into the Derry home.
The 81-bed facility is for people with learning difficulties, mental health issues and dementia.
“It is 15 months on since I published a report into care failings in Dunmurry Manor and many of the recommendations that were in that report around staffing, around complaints, around care issues, it is depressing to hear many of these seem to be surfacing in Owen Mor,” Mr Lynch told BBC Radio Foyle.
Mr Lynch published his report into Dunmurry Manor in June 2018.
He said there was an onus on all authorities to ensure care at the Londonderry home “improves now.”
“We can’t afford to wait another number of months to fix the problems,” he said.
“What residents and families need is action now.”
Owen Mor nursing home in Londonderry first came under the spotlight in May following an inspection.
Inspectors highlighted concerns about staff knowledge, including nurses not following policies and procedures, as well as inadequate records about areas of patient safety, such as falls, feeding and nutrition.
After a follow up inspection in August, the regulator formally stopped new patient admissions after obtaining a court order – an unprecedented move, according to the RQIA.
Management apologised on Sunday that care has “fallen short of our regulatory requirements.”
“At Owen Mor our priority is to deliver the highest possible standards of care with compassion,” they said in statement.
“We apologise to our residents and their families that, over the past few months, we have fallen short of our regulatory requirements and are working to ensure that these are fully reinstated.”
The home’s management said it is “working closely with our regulator the RQIA and the Western Health and Social Care Trust to address the four outstanding compliance issues.”
“We regret the unavoidable delays in achieving full compliance and any knock-on effect this has had due to the suspension of new admissions.
The statement goes on to reassure residents and their families about the standard of care and that complaints are robustly and rigorously investigated.
Last week about 80 people attended a public meeting in Derry about the troubled home.
One family, the Stewart’s, described their experience of the home as “horrendous”.