Dr Horgan will make the submission on behalf of Clyde's hospital, which operates at or beyond capacity for a "significant" part of the time.
The report, which was released last week, said bed numbers in rural hospitals throughout Southland and Otago were adequate until 2026 and could be reduced by up to 30% if more people were treated by primary health services in the community.
Dr Horgan said despite the overall numbers in both regions being adequate, Dunstan Hospital generally ran at more than 85% capacity, and cutting Central Otago admissions by 30% was not achievable.
She said the estimated 30% reduction in future admission numbers was based on Ambulatory Sensitive Hospitalisation (ASH), which characterised a hospitalisation that possibly could have been avoided with adequate primary health care.
"The word 'possibly' is very much part of the equation. Any reduction in ASH must also take into account whether, or how, primary health care can facilitate that reduction. A 30% reduction in Central Otago is unachievable."
Dr Horgan's submission will address whether the report acknowledged input from rural health organisations - including Dunstan Hospital - made on the first draft.
"I read the first draft and made some additions to it, and now we are digesting the released draft to see how they were incorporated. What our submission says will depend on the report detail."
Otago District Health Board elected member Malcolm Macpherson said when the report was released last week that regardless of the report saying bed numbers in Otago and Southland rural hospitals were adequate until 2026, Dunstan Hospital was at capacity.
Hospitals could not easily move people around the region to "soak up" beds available elsewhere, he said.
He said it was unlikely Dunstan would come close to achieving the report's projected 30% reduction in future hospital admission numbers by treating people in the community.
