The health board yesterday confirmed it would partner with Healthcare of New Zealand, Access Homehealth and Royal District Nursing Service New Zealand to introduce a new model of care for providing home and community support services across the Southern district.
It was also announced Presbyterian Support Otago staff would be transferred to one of the new providers.
The decision has shocked Presbyterian Support, which has vowed to fight.
Chief executive Gillian Bremner said their tender was not declined on financial grounds, and the reasons for not getting a contract were vague.
The organisation was now getting a legal opinion on ''the merit of a legal challenge to the decision'', she said.
Presbyterian Support Otago board chairman Frazer Barton said the organisation would be like ''a dog with a bone''.
''How can we sit back and let this happen to our clients, staff and indeed, the community, without fighting the seemingly inexplicable decision?''We must challenge why we were unsuccessful, why our high level of service to vulnerable people was rejected, why we are now required to transition our experienced and qualified staff to three providers with far less local footprint than we have.
''There are far too many unanswered questions to let this bone go without a fight.''
Mrs Bremner said the organisation was also looking at the involvement of Prof Matthew Parsons, of the University of Auckland School of Nursing, whom she said worked for one of the chosen agencies one day a week.
''He has been a consultant to the DHB throughout this process in the design of the service model. We want to know how the DHB managed this conflict of interest.''
However, Prof Parsons last night said he had no involvement in the SDHB's selection process or involvement in supporting providers who won contracts.
He also denied working one day a week with any of the successful agencies.
''The only involvement the university has had has been around the development of the new model, as it has done with a number of health boards around the country.''
Southern District Health Board finance and funding executive director Robert Mackway-Jones yesterday said the board had a robust process which included disclosure of any conflicts.
Mrs Bremner said that from the outset of the tender process the SDHB had said it would consider between two and four providers.
It chose three.
''We want to be that fourth provider. It would also mean our clients and staff will suffer the least amount of disruption to their lives as possible as the SDHB works through the new service provisions.''
Presbyterian Support Otago would hold as many meetings as it would take to get a resolution, Mrs Bremner said.
The first meeting would be held with the SDHB chief executive today, she said.
Mr Mackway-Jones said the ''preferred providers'' all had significant experience in working with the new model in other parts of New Zealand, and the DHB was confident it offered high quality services.
''This process has been about improving services and, most importantly, the new model of care will mean much greater flexibility so that services can be better tailored to help individual clients and their whanau achieve their goals.''
Registered health professionals would lead the service, with increased training for support workers, to make it more equitable and consistent across the district, better co-ordinated with other health care providers, and faster and easier for clients to access, he said.
Affected PSO staff would be transferred to a new provider, in line with the DHB's tender requirements and protection provided by employment relations legislation.
The DHB had been working to ensure all clients and staff were informed of the changes, and supported through the transition, he said.
Meetings would be held for clients, families and community groups to learn more about the new providers and the new model of care.
The changes would start in March next year, he said.
''At that time, we will begin a three-month transition process when some clients will transfer to a new provider.''