Two Middlemore Hospital nurses have been attacked on their way home from work this morning.

Photo: RNZ / Claire Eastham-Farrelly

The unprovoked attack happened at 7am this morning near the western carpark entrance, leaving one nurse with broken bones.

Counties Manukau District Health Board chief executive Margie Apa said the staff, who both worked in the Intensive Care Unit, were leaving from their night shift.

"The attackers were hiding behind a wall and I understand knocked one staff member down from behind, and broke the collar bone of the other staff member," she said.

Ms Apa said the attackers then ran from the scene, but the identity of the attackers was obscured from cameras, due to fog.

Counties Manukau security staff were working to obtain other security camera footage.

Ms Apa said Middlemore had increased security at its carpark sites since May last year, with a further increase in security staff in December.

"We are appalled and devastated that any of our staff, all of whom dedicate their professional careers to saving lives, have to experience this kind of unprovoked violence," Ms Apa said.

However, the New Zealand Nurses Organisation says the assault of two Middlemore Hospital nurses could have been avoided, if the district health board had listened to safety concerns raised.

The New Zealand Nurses Organisation held a rally outside Middlemore Hospital in December to highlight the lack of security at the parking areas staff have no choice but to use.

The organisation said the parking lot was not fenced or secured and there were no security guards at the entrance or exit.

The organisation's second-in-command national delegate for Middlemore, Sela Ikavuka, said staff were angry and scared.

"One of my colleagues told me in the other car park at 6.45am there were two strangers yelling at staff walking into the hospital, so it could have happened at either car park," she said.

Ms Ikavuka said they've repeatedly asked for better safety measures at staff carparks for more than a year.

"I don't think the DHB can put it off any longer, it had to come to this, our members being attacked for them to wake up and finally do something about it," she said.

She said the organisation is wanting immediate permanent security guards in place from 9pm today through to 9am, which the DHB has now agreed to do.

Anyone with any information on the attack is being urged to contact Middlemore Hospital security or the police.