The document, which each DHB is required to have under the Ministry of Health national health emergency plan, sets out how emergency planning and response are to be managed.
The plan is activated when a local, regional or national incident meets the definition of a "health emergency" — when usual resources are overwhelmed or have the potential to be overwhelmed.
That includes situations such as pandemic, earthquake, major weather events, loss of services or industrial action.
The SDHB’s 2014-17 document remains in place until the 2018-21 plan is completed.
Southern DHB emergency management manager Paul McNamara said the new plan was in draft form, and was about to be sent out for consultation.
Parties asked to comment on the new plan include the Ministry of Health, Civil Defence emergency management groups, emergency services and WellSouth PHO.
"The current plan, and the draft 2018-21 plan, are designed around ensuring that during any emergency (no matter how big or small or whatever the cause) the Southern DHB is prepared to continue service provision to the community during the event wherever possible," Mr McNamara said.
Consultation was planned to start on August 27 and run until September 17, with the final plan being sent to the SDHB executive leadership team for sign off by early October.
The plan took an "all-hazards" approach to planning, Mr McNamara said, which meant the process for managing an event was standard, whatever the cause.
"For example, events such as loss of water to Dunedin Hospital can be caused by a number of factors such as a contractor breaking the water main, an earthquake or, as happened recently, untreated water entering the CBD water system."
Drafting a new health emergency plan was not the only crisis planning the health board had been undertaking, Mr McNamara said.
Along with other South Island DHBs it had helped prepare Safer — the South Island Alpine Fault earthquake response framework — as well as the integrated air operations plan and fuel plan, he said.