A Facebook message from Absolute Midwifery (Independent Midwives in Dunedin) said the staff shortage meant the hospital was unable to provide postnatal care to women who were medically fit to be discharged home after their births.
Those who had Caesarean sections or needed to be monitored after birth were transferred to the surgical ward or paediatric ward with their babies, to be looked after by the nurses there.
In a statement, Southern District Health Board midwifery director Karen Ferraccioli said a "collective intra-hospital approach" was taken to keep postnatal women and babies in a safe and welcoming environment.
"The postnatal wing has been relocated on the antenatal side of Queen Mary maternity floor, accommodating postnatal women/people in need of complex care or recovering after birth, and their babies.
"Centralising our staff resources in one side of Queen Mary maternity ward has optimised the use of our resources and our capacity to respond to the need of our customers, and their families.
"A maternity pod annex (MPA), a temporary flex space located on the surgical ward, has been set up mirroring the postnatal facility."
A Dunedin midwife, who declined to be named, believed the staffing shortage was unsafe and it would occur with increasing regularity in future.
She said it had happened because midwives were not treated fairly or paid fairly, and they were leaving the profession in droves.
The "no [Covid] jab, no job" policy had also contributed.
"So now we're finding ourselves in situations where there is no staff for postnatal care."
She said there had been critically low staffing previously, but this was the first time it had caused the closure of the ward.
Lead maternity carers (LMCs) in the community had been able to fill core staffing shifts at the hospital previously, but that was not possible this weekend.
"There's just no staff.
"It's not safe for mothers and babies."
It was only a matter of time before things became critical in the delivery suites as well, the midwife said.
"Staff could be busy in one delivery suite and they may be needed in another room.
"If there's only two or three staff across the delivery suite floor, there might be one woman that's taking up all those staff.
"It's becoming really critical in there. Hopefully this is a wake-up call for the Government."
Long-serving Dunedin midwife Maureen Donnelly said the situation had been caused by politicians and DHB chief executives who had turned their backs on midwives for years.
She said staffing gaps were previously filled with midwives from overseas, but now that Covid had arrived, the situation had been laid bare.
"They've been told this is coming and they've ignored it and ignored it and ignored it, until the ambulance has gone off the cliff and it's now drifting out to sea.
"Midwives have been trashed to the ground — they've been destroyed by politicians and media, and now we have just about none left."
National Party Dunedin list MP Michael Woodhouse said it was an "extraordinary development that was foreseeable for months, if not years".
"Quite frankly, it's got to be fixed immediately. The risks to mothers and babies is horrendous."
He said the Government's "terrible" treatment of LMCs had led to a number of them leaving the independent midwifery profession.
"The Government has had a report for four years that says what an independent midwife should be paid.
"They've ignored it, they've thrown the profession crumbs and this is the inevitable outcome of it."
He said there needed to be a comprehensive strategy for reattracting midwives back into the profession and providing safe maternity care for mothers and babies.
"The Health Ministry and the minister need to look very carefully at why this has occurred because it won't be the only DHB in the country where this is happening.
"Midwifery is in crisis."
Health Minister Andrew Little was unavailable for comment yesterday.
Government duty minister and Dunedin Labour MP David Clark declined to comment on the matter yesterday.
"As this is a staffing matter, it is operational, and therefore more appropriately dealt with by Southern DHB directly," he said.