The requirement is part of the parties obligations under the nurses and midwives' national employment agreement with district health boards.
Savings have been set across the country for efficiencies expected in each district health board.
The Otago board has been struggling with high levels of vacancies, particularly in nursing, and Ms Bradfield told the hospital advisory committee's latest meeting she felt achieving the $1.8 million was "the challenge of the century".
Both the Otago and Southland boards have begun work with the New Zealand Nurses Organisation on the issue and Ms Bradfield said there was a common aim to achieve as much as possible in a way which was as painless as it could be.
The boards had to be mindful of honouring the employment agreement's safe staffing and healthy workplace requirements and there was a tension between that and finding efficiencies.
Both boards were seeing how they met requirements, particularly for leadership across wards, units and after hours and for having processes for staff to follow when staffing was less than desirable and could compromise safety.
An Otago-Southland joint action committee had been formed involving board representatives and the union working collectively.
The emphasis was on joint responsibility, she said.
Board chairman Richard Thomson said the Otago board was fortunate in the calibre of people it had to work with in the nurses union.
These people were " very grounded in Otago and have Otago interests at heart. Even if we have the odd spat there is genuine respect shown in both directions."
Dunedin Hospital's emergency department expects to be named next month as one of the nine pilot sites around the country for a project designed to improve patient flow, called Optimising the Patient Journey (OPJ).
The project will use what is known as the " lean thinking" method used by companies such as Toyota.
It encourages staff to make small but practical changes to their work.
Staff identify where time is being wasted and find ways to improve systems.
Hospitals which used the method found eliminating much of the unnecessary walking by staff had freed up time for patients.
Dunedin Hospital's patient flow project, which began last year, followed patients through the hospital to identify where delays occurred. It was based on similar principles.
Project manager Graham Bugler has indicated that this project is likely to be combined with the national three-month OPJ pilot.
