Health New Zealand say further initiatives are being put in place to manage the high demand at Christchurch Hospital

The hospital's been operating above 100 percent capacity, with patients treated in corridors and some waiting more than 24 hours to be seen.

Staff have raised concerns on the hospital's capability to cope in a mass causality event.

Canterbury Operations Group Director, Hamish Brown says the ED has been in and out of critical overload for the past four weeks - using every available space to safely care for patients.

He says they're working to enable faster admissions and is assuring people systems are in place should a mass event occur.