Portadown have been awarded the points and a 3-0 win from the Boxing Day derby against Glenavon.
It comes after Glenavon defender David Elebert had been due to serve a suspension but started the game.
“Glenavon has been charged by the Irish FA Disciplinary Committee with a breach of Article 22.1 (ineligibility through suspension) of the Irish FA Disciplinary Code,” confirmed an IFA statement.
“The club has been fined £350 and will forfeit the match against Portadown FC, played on 26th December, by the score of 3-0.
“Should it wish to, the club now has four days in which to submit a disciplinary challenge to the Disciplinary Committee.”
The game finished 2-2 on the pitch as Glenavon came back from 2-0 behind to snatch a last gasp draw.
Glenavon will decide at a board meeting on Thursday evening whether or not to appeal the sanction.