More than 1000 people attended a meeting in Dunedin on Monday night to push for the retention of neurosurgery services in the city.
The meeting was also attended by a panel established by the Ministry of Health to look into the future of the service.
All South Island district health boards want a regional neurosurgery service, staffed by six surgeons.
But the Southern District Health Board disagrees that it should be consolidated in Christchurch.
Panel chairwoman, Auckland paediatric surgeon Anne Kolbe, said she has taken note of the message from the people of Otago and Southland.
A similar meeting will be held in Invercargill on Thursday. On Wednesday, the panel will hear from southern mayors and more health specialists.
Other members of the panel are consumer advocate David Russell and an Adelaide neurosurgeon Glenn McCulloch.
Last week, a petition with 45,000 names was delivered to Parliament.