Attorney-General Elise Archer has not commented on why she sought advice from the Solicitor-General and subsequently intervened in the Lake Malbena appeal because it was an ongoing legal matter.
The appeal was lodged by the developer of a proposed luxury tourism development on Halls Island, at Lake Malbena in the Walls of Jerusalem National Park.
The proposal was voted down six councillors to three at a council meeting in late February.
In a budget estimates hearing, Greens leader Cassy O'Connor asked Ms Archer why she sought to intervene on a jurisdictional question which has been around for two decades "after a crushing defeat."
"You conveniently joined an appeal by a developer," Ms O'Connor said.
Ms Archer said it was a normal part of the Attorney-General's role to intervene in court proceedings seeking the answer to a legal question, in this case seeking to clarify a jurisdictional issue.
"It's one of the non-political roles of the Attorney-General, as the first law officer, to intervene on proceedings to seek clarification," Ms Archer said.
"This appeal raises important issues relating to the validly of Tasmania's laws."
Ms Archer said she could not go into more detail as the appeal was still before the court.
"I'm acting on legal advice in my capacity as first law officer. I'm not going to provide a commentary on advice - it would be extremely inappropriate for me to do so," she said.
Ms O'Connor questioned why Ms Archer suddenly joined an appeal that, if successful, would remove the power of councils over reserved lands with management plans in place.
"It is really hard to see it as an apolitical action as it is designed to prop up the policies of the day," Ms O'Connor said.
Mr Archer said she would wait the court's decision and examine the judgement at that time.