A Santana announcement on Monday said the mining company had "executed binding agreements" to acquire on a freehold basis "the lands on which the project and its infrastructure are located".
Another announcement last month said it owned "all areas directly affected by the proposed mining operations".
However, although two farmers have sold land to Santana subject to Overseas Investment Office approval, two other areas within the proposed site remain in public ownership.
The unsold land is occupied by two roads - Thomsons Gorge Rd and Shepherds Creek Rd - both owned by the Central Otago District Council .
Sustainable Tarras deputy chairman Rob van der Mark said it was simply not true Santana owned all the land it wanted for the mine.
"We are deeply concerned that the firm appears to be misleading investors by not mentioning the public road ownership."
Mr van der Mark also flagged that the issue had "not been communicated transparently to the local community, who collectively own the roads".
"It is really important that the community is fully informed of all the facts and made aware of any opportunities to engage in the process [of the mine proposal], particularly any opportunity to be consulted on sale or access to this public land."
Thomson Gorge Rd traverses an area where Santana plans open-cast pits and the road also provides access to the historic, restored Come in Time battery built during gold rush days.
Shepherds Creek Rd, which has archaeological significance due to its construction during the gold rush, runs through the area where Santana wants to build a processing plant and dump mining waste known as tailings.
A CODC spokesperson confirmed Santana, as required under the Crown Minerals Act, had been negotiating for "access to council-owned land within the mining area".
Councillors had been updated at meetings in May, July, September and October, Santana chief executive Damian Spring attending the September meeting.
A memorandum of understanding, that enabled an access agreement to be drafted, had been agreed, but to take effect, any drafted access agreement would have to be approved by council.
If approved, an access agreement would trigger a legal process for consideration of the stopping, and possibly selling, of the roads, using the Public Works Act or Local Government Act.
Mayor Tamah Alley confirmed the council had not "signed or approved any formal agreement" with Santana about use of the land the roads occupy.
The ODT asked Santana why it had implied to shareholders it had all the land required for its mine.
It did not answer the question, but confirmed it had been referring to Ardgour Station and parts of Bendigo Station it had bought subject to OIO permission.
