Southern District Health Board managers say proposed changes to Wakatipu health services will not save the amount the National Health Board suggests, but has stopped short of providing its own clear estimates.

The NHB-appointed expert panel, which was given the task of providing a clinically and financially sustainable service for the Wakatipu, estimated its proposals would save almost $657,000 this year.

It also predicted savings could rise through the years to more than $1.06 million a year by 2018-19.

The detailed financial analysis did not form part of the panel's August report, which described its proposals as cost-neutral. The analysis was later provided to the Otago Daily Times and the DHB after they requested it.

In a report to go to the board's last meeting for the year in Invercargill today, acting chief executive Lexie O'Shea noted managers "comments" on the analysis.

Managers did not agree with the NHB's view there would be a net gain of $800,000 in the second year of the model.

The model was presented from the perspective of a service provider rather than looking at the incremental costs to the district health board as a whole.

The NHB model showed revenue from outpatient clinics and CT scans exceeding their cost increases over time.

However, under population-based funding, increased activity did not result in greater funding, apart from demographic funding increases, her report said.

The 2% demographic funding increase assumed in the NHB report for the Wakatipu area was higher than the 0.9% received by the board this year and also higher than the 1.75% overall increase for the whole country.

It appeared the NHB had allocated $39.8 million as the population-based funding base for the Wakatipu, but such funding was not designed to be isolated in this way.

Overall funding was aligned to health need and critical mass in infrastructure over the whole DHB area.

Management questioned the net financial gain of $84,000 for the proposed introduction of a CT scanner.

While the bulk of the funding for this scanner was expected to come from the community, the NHB figures did not show the incremental costs the DHB would incur, such as paying for or contributing to a number of public scans, the report said.

Suggested savings of $140,000 from having more outpatient clinics at Lakes District Hospital at Frankton were also questioned. This figure did not take into account incremental costs, and the assumption additional travelling time for clinicians would be offset by reducing travel and accommodation "is unlikely", the report said.

• The panel proposals include retaining and enhancing services at Lakes District Hospital, developing a centre of excellence for training rural health practitioners and having a CT scanner in Central Otago.