Work had already been carried out on the building at Doc's expense, which would benefit the potential concession-holder, said Bruce Mason, of Omakau, and John Bellamy, of Dunedin.
That implied a decision had already been made in favour of the concession being granted, they said.
James Cameron, of Christchurch, has sought a 10-year concession to develop the 102-year-old building and operate it as commercial accommodation.
The application attracted 195 submissions, 190 of them opposing the plans. A five-hour hearing was held in the Becks Hall yesterday, with 14 submitters airing their views to Southland Conservancy Doc community relations manager Martin Kessick.
He adjourned the hearing for more evidence to be heard in February. Then he will prepare a report for Otago Conservator Marian van der Goes, who will make the decision on the matter.
The main concerns of the opponents were that the public would be denied access to the building, and that the post office, which featured original fixtures and fittings, would be modified "irreversibly" for accommodation.
"This consultation on a so-called proposal is a sham - major financial commitments have been made and are now being affected by work in progress including new plumbing/sewerage. This would not otherwise be needed for public purposes," Mr Mason said.
Central Otago Doc manager Mike Tubbs said Mr Cameron had been allowed to carry out "minor work" on the building, including some plumbing.
Outside the hearing, Mr Cameron, a former St Bathans resident, told the Otago Daily Times he was not surprised by the level of opposition to his plans.
"But it's a shame that certain people oppose proactive projects in this economic climate," he said.
Vulcan Hotel owner Mike Kavanagh supported the concession and said Mr Cameron was "not a fly-by-night developer from Auckland, or Queenstown, or Christchurch; he's here to do a job".
Lawyer for the St Bathans Heritage and Environment Preservation Trust Kristy Rusher said the concession should be declined as the application contained insufficient information, there was no way of avoiding, remedying or mitigating the adverse effects of the activity, the concession was contrary to the purpose of the Goldfields Park Historic Reserve and not consistent with the Otago Conservation Management Strategy.
