The Southland board meets on Thursday to decide whether it should join Otago in recommending to Health Minister Tony Ryall that he establish one Southern DHB.
Mr Menzies said Thursday's decision would be a momentous one, but part of the consultation process was the desire for the boards to have a hand in shaping their own future.
Late last week, about 400 members of the New Zealand Nurses Organisation at Southland Hospital followed the lead of 24 senior doctors by raising issues publicly about the merger process.
Mr Menzies said yesterday he was not precluding the possibility of meetings with the two groups before Thursday, but none had been planned.
He had yet to receive the nurses' letter and was not sure if their concerns were substantive.
NZNO convener at Southland Hospital, Anne McFarlane, said nurses saw the retention of nursing leadership in Southland and Dunedin as a pivotal part of any merger.
NZNO's submission in support of the merger had been conditional on this, but the Southland nurses did not feel the detail provided in the consultation process or subsequent report considered this issue.
Mr Menzies noted that the regional chief nursing and midwifery officer, Leanne Samuel, was from Southland.
The merger proposal was designed to ensure service levels were retained rather than diminished.
No merger would be more of a risk than a merger, he said.
Twenty-four of about 90 Southland senior doctors last week sent an open letter to Mr Menzies saying the consultation process was too short and did not give enough information on which to base a decision.
They wanted to see a full risk-benefit analysis, and were concerned about possible Southland disenfranchisement under a board in which Otago had four elected members and Southland three.
Meanwhile, Queenstown Medical Centre has urged the Southland board to vote for the merger.
Centre chief executive Dr Richard Macharg said concern about the potential loss of autonomy in Invercargill had to be carefully balanced against the likely health gain for Central Otago and rural Southland patients.
Co-operative work arrangements had been impossible to implement in the past seven years because of separate funding systems for the two boards, he said.
