A deadly coronavirus outbreak at a rest home spread so rapidly that there were a number of "safe practice issues", including how protective equipment was used.
Rosewood Resthome and Hospital in Christchurch is now linked to six deaths and 33 confirmed or probable Covid-19 cases, of which 18 are staff members.
Many staff had to go into isolation and that led to shortcomings, Canterbury DHB confirmed to the Herald.
"In the demanding context of managing a cluster of frail elderly residents, a significant number of staff needed to be isolated because of exposure to Covid-19 and this contributed to a number of issues regarding safe practice, including the way PPE [personal protective equipment] was used," a DHB spokesman said.
"Canterbury DHB is increasing support to the aged residential care sector in Canterbury with teams of experts in caring for the elderly and in infection prevention and control going out to give further support and guidance as we work together to protect the safety of residents and staff."
Another Christchurch aged-care facility, George Manning Lifecare and Village, is dealing with its own Covid-19 outbreak. Canterbury DHB will review the response and preparedness of both rest homes "as soon as it is appropriate to do so", the spokesman said.
"This Covid-19 pandemic is an unprecedented challenge for us all, especially for those working in aged residential care, who are responsible for caring for the most vulnerable members of our society.
"Dedicated managers and staff in these facilities have been working proactively with us to keep their facilities safe through restrictions on visitors and infection and prevention measures such as hand hygiene, environmental cleaning and disinfection and the use of PPE to reduce the risk of transmission."
Rosewood Resthome referred all comment to Canterbury DHB. The Aged Care Association has been approached for comment.
The Director-General of Health, Dr Ashley Bloomfield, has said there may be more deaths linked to the Rosewood outbreak, because of residents' underlying health conditions.
The ministry's website listed the cluster's origin as "unknown". The DHB has previously said it was highly likely a staff member took the virus into the unit, given strict visiting restrictions under the alert level 4 nationwide lockdown.
On Monday last week 20 residents from a dementia unit were moved to an isolated area of Burwood Hospital, to try to contain the spread of the virus. Six of that group have died.
Twenty of the residents remaining at Rosewood will be moved to other aged-care facilities providing hospital-level care over the course of this week. That will leave 24 residents at Rosewood, which is undergoing thorough cleaning.
The DHB has appointed an acting manager to Rosewood Rest Home. The DHB spokesman said that was originally done "to give the facility manager a break but also because they were one of a number of Rosewood staff had to go into isolation due to being in contact with people later found to have Covid-19."