The midfielder has been referred to the national disciplinary commission along with seven other players as part of an investigation by the Italian Football Federation and is facing allegations of sporting fraud relating to two matches against Genoa and Lecce at the end of the 2011 Serie A season.
Mauri is alleged to have broken the rules regarding the "principles of loyalty, fairness and integrity" as well as on the "prohibition of betting".
However, the player's agent, Matteo Melandri, insists that his client - who was arrested and subsequently released in 2012 amid match-fixing allegations - is innocent.
"We're not surprised (he's been referred) because all of the papers have been talking about it," Melandri told Sky Sports 24.
"Compared to the findings in Cremona (as part of the earlier investigation) I do not think there are any new elements.
"But if we have to prove (his innocence) again, we will do so."
On Tuesday, Lazio released a statement on its website backing the 33-year-old to prove he is not guilty.
"We reiterate our confidence (in Mauri) and have always claimed innocence in both a disciplinary and criminal case," the statement read.
"We assume that this case will be able to prove Stefano Mauri's innocence against these alleged facts and will eliminate suspicion."