Mauri and seven other players are under investigation by the Italian Football Federation (FIGC) for alleged sporting fraud relating to two matches against Genoa and Lecce at the end of the 2011 Serie A season.
And with the trial expected to go ahead on July 24, the 33-year-old has insisted he did not break any regulations.
"I'll see what happens in the process, but I am calm," he told reporters.
"I know how things went; I know I never went beyond the rules."
Lazio, Genoa and Lecce could all face points deductions while players involved could receive hefty bans if found guilty of the charges, but the Biancocelesti have lent their backing to Mauri.
The club released a statement saying: "Lazio have taken note of the referral given by the Disciplinary Committee, referring to the games Lazio-Genoa and Lecce-Lazio dating back to 2010-11.
"We reiterate our confidence [in Mauri] and have always claimed innocence in both a disciplinary and criminal case.
"We assume that this case will be able to prove Stafano Mauri's innocence against these alleged facts and will eliminate suspicion.”
The other players being investigated are Massimiliano Benassi, Mario Cassano, Stefano Ferrario, Carlo Gervasoni, Omar Milanetto, Antonio Rosati and Alessandro Zamperini.