Vella was appointed as a Magistrate in 2015 upon decision of Joseph Muscat's cabinet.[2]
Over a decade, she presided over numerous cases in the Magistrates’ Court, including criminal prosecutions and inquiries. In Gozo, she heard cases before the Civil Court (First Hall), Family Court, the Agricultural Rent Regulation Board, Rent Regulation Board and Court of Magistrates in its civil jurisdiction. She also presided over Malta’s Rent Regulation Board, and sit in the Court of Magistrates for both civil and criminal jurisdiction.
In 2021, Vella was removed from the Gozo Court and reassigned to the Law Courts in Valletta as part of administrative changes to manage case distribution.[5] Data from 2019 and 2020 indicate that Vella had a substantial caseload before reassignment.[6]
In October 2024, Judge Wenzu Mintoff publicly reprimanded Magistrate Monica Vella for "irresponsible behaviour" causing unnecessary delay to proceedings. Mintoff addressed the communiqué to the justice minister, the chief justice of Malta and the court registrar.[7]
In 2025, Vella became the subject of formal disciplinary proceedings before the Commission for the Administration of Justice of Malta, following complaints about delays in issuing written decisions and other administrative failings. She was suspended from her duties for one month on half pay, a decision that was confirmed on appeal and could be further reviewed by the Constitutional Court.[8]
During the disciplinary process, reporting noted that Vella had one of the higher numbers of pending criminal and tribunal cases among her peers, although staffing and other factors may have contributed to delays.[9]