Gibbs said the Auckland DHB had been impacted by the current shortage of midwives despite having the resourcing to employ more.
"There are not enough midwives available nationally or internationally to fill our vacancies at this time.
"In response, we decided to temporarily trial a more compact maternity service in order to improve midwifery staffing levels, and to ensure midwifery and nursing staff are able to deliver the standard of care they aspire to provide."
She said the decision was made after careful consideration, including an analysis of patient flow in our maternity services.
"Many patients will benefit from having higher numbers of midwives per shift on their ward."
Gibbs said the DHB believed the health and wellbeing of midwifery and nursing staff needed to come first in order to provide a sustainable maternity service for women and their babies.
"For this reason, we are taking a new approach to service provision in our maternity service at Auckland City Hospital."
The DHB could not say when or if the ward would reopen.