Mr Rousseau spoke at a Waitaki district health forum last night about the Otago and Southland district health boards' review of hospital capacity in the southern region.
If nothing was done, he believed it would be just a matter of time before smaller rural hospitals and small secondary hospitals could not attract clinical staff.
Providing regional clinical services was being examined across Otago and Southland and possibly South Canterbury.
The aim was to create a model with greater sustainability.
There were "enormous challenges" around population-based funding and it was very difficult to sustain services.
Beverley McCaw said it was good that the ODHB had rolled over the Waitaki District Health Services contract for a further three years.
She questioned whether that meant Waitaki services were "safe" for the next three years.
Mr Rousseau said Oamaru Hospital was not going to close and he would like to see services improved, with more visits from Dunedin clinicians.
However, equally challenging was how to live within funding constraints and that meant doing things more efficiently.
The hospital capacity review would look at Waitaki's population, which did not appear to be growing.
Another problem was attracting clinical staff, as visiting clinical services could not be relied on.
Otago MP Jacqui Dean wants the health board and Waitaki District Health Services to discuss access to Oamaru Hospital's CT scanner for all patients.
She is concerned publicly-funded Waitaki patients have to go to Dunedin for CT scans because the ODHB holds the contract.
Mrs Dean met ODHB chairman Richard Thomson in Oamaru at the weekend to discuss the issue and said she hoped the two bodies would work towards making better use of the Oamaru scanner.
