In June, both district health boards decided not to wait for a national policy on the funding of private tests, but no suggested date for the change has been given.
The Otago board expects to save an estimated $1 million a year from the change and Southland $300,000.
Such projections have been questioned by opponents of the move, who point out that the Capital and Coast board, which already has the service, did not save as much as expected.
When the Otago board voted on the issue, the vote was split and the decision of both boards to go ahead depends on their being satisfied with the implementation plan.
Some members expressed disquiet about making a decision when they did not know how exceptions might be dealt with or how any detrimental effects would be monitored.
Among other concerns were the costs of tests, which were expected to be higher than those negotiated by the board, and issues which could arise when care was transferred from a public to a private clinician.
Board managers are working on the implementation plan with Southern Community Laboratories, which provides laboratory services in the South.
Board regional planning, funding general manager David Chrisp told the board there was a tentative target date for introducing the change.
One of the issues being discussed was what was meant by private specialists.
Board member Dr Branko Sijnja said another issue was the mechanism for recovering the cost of tests.
He reminded board members that when hospitals were charging for some services some years ago, the cost of charging was higher than the cost of recovery.
Board chief executive Brian Rousseau said deciding whether the patient or the specialist would be billed would be something for SCL to sort out.
Mercy Hospital chief executive Michael Woodhouse said he did not believe private specialists wanted to "have a bar of this", not wanting to be an intermediary between the laboratory and the patient.
SCL chief executive officer Dr Peter Gootjes said there were many issues still being worked through with the board, but he was hopeful they would be resolved and the work completed later this year.
