Miss Moore (19) won last month's election and survived an investigation into two complaints about aspects of her campaign.
However, she was disqualified after an appeal was upheld by independent arbitrator Prof Paul Roth, of the University of Otago's law faculty.
Among other concerns, Miss Moore says she was not informed the appeal was under way and that was a breach of natural justice.
The OUSA obtained a legal opinion saying the executive did not have the power to overturn Prof Roth's decision.
However, Miss Moore said yesterday her lawyer had written to the OUSA executive saying she believed the executive did have the power to override Prof Roth's decision.
If that happened, the executive could appoint a new independent arbitrator, or declare the presidential election null and void and hold a by-election.
"My lawyer has written to them suggesting they seek a second legal opinion."
She said her legal advice was Prof Roth's decision was made "too quickly".
She also claimed Prof Roth was given material about her campaign activities she had not been shown, including photographs, pages from her Facebook page and comments from four people.
The information post-dated the initial complaints about her, she said.
Not having access to the new information or being given an opportunity to respond to it was a breach of natural justice.
Miss Moore said she understood the OUSA had received her lawyer's letter and discussed it at a routine executive meeting on Tuesday night.
However, OUSA 2008 president Simon Wilson said yesterday he had not seen the letter and no discussion had taken place on Tuesday.
The executive had delegated authority to a standing committee to consider any information relating to the election.
The members of the committee were finance and services officer Kieran Knight, education officer Matt Tucker, welfare officer Tania Cumming and himself.
