Every St. Patrick’s Day the state’s leading politicians flock to South Boston for a roast that features jokes, songs, and lots of laughs. Most of the pols view the event as good politics, but state Auditor Suzanne Bump regards it as part of her official duties.

Bump, unlike the governor, attorney general, and treasurer, billed the state for mileage (just two miles) to and from her South Boston condo to the St. Patrick’s Day breakfast at the Boston Convention and Exhibition Center. Records show she has also billed the state thousands of dollars for mileage to speaking engagements across Massachusetts that could benefit her politically.

Bump, who declined to be interviewed, said through a spokesman that her trips around the state, including her attendance at the St. Patrick’s Day event in March (where her planned speech got bumped because of time constraints), are part of her official job.

“It is customary and appropriate for elected officials to address groups of interested citizens about their priorities and the work of their offices and to participate in civic celebrations,” said Bump spokesman Christopher Thompson. “They are, after all, accountable to the public. Auditor Bump has always been careful to distinguish appearances made in her official capacity from those with a political purpose. Thus, mileage incurred when she addresses a League of Women Voters dinner is reimbursable, while that incurred attending a Democratic Party meeting is not.”

The line between official and campaign activities has become an issue for Bump since her former top deputy, Laura Marlin, sued the auditor in federal court, claiming that she was wrongfully terminated after she complained that Bump was conducting campaign activities from her State House office.

Marlin claimed that Bump scheduled a meeting at her State House office with members of the Service Employees International Union Local 509 to seek the group’s endorsement. The meeting was subsequently moved elsewhere after Marlin raised concerns about it.

In a court filing, Bump denied Marlin’s allegations and said she fired her aide because “her ongoing rude, disrespectful, and confrontational behavior towards her colleagues, including Auditor Bump, were an impediment to the smooth and efficient functioning of the office.”

Expense records obtained from Bump’s office under the Public Records Law indicate the auditor was on the road every few days over the last 1½ years, from January 2013 to June 2014. During that period, she billed the state nearly $5,000 for in-state trips, mostly for mileage at 45 cents a mile.

Many of the trips could easily be viewed as part of her official duties. She met with the League of Women Voters at the South Shore Country Club in Hingham and the editorial boards of newspapers in Quincy, Lowell, Worcester, and Fall River. She attended Boston Mayor Marty Walsh’s inaugural and the Martin Luther King annual breakfast at the convention center.

Yet the official purpose of other trips is less clear. She billed the state for mileage for numerous trips across the state to conventions and breakfasts hosted by union groups, which have been a good source of campaign funds for her — $45,000 since 2010. She also traveled to many chamber of commerce meetings, retirement parties, and a variety of charitable events such as Valentines for Vets, Goodwill’s Thanks-for-Giving, the Brockton Holiday Office Gift Wrap, and the Families in Transition Holiday Party.

In addition to the 90 cents in mileage payments she received for the trip to the St. Patrick’s Day breakfast in South Boston, Bump put in for $2.70 to attend the funeral in Dorchester of former attorney general Robert Quinn. She also collected 90 cents for mileage to the Boston Harbor Hotel for a luncheon put on by the Chief Executives Club and another 90 cents for a luncheon with US Sen. Elizabeth Warren at the Seaport Hotel, which was hosted by the Commonwealth Institute, an organization of female executives.

“She’s acting entitled and petty,” said Patricia Saint Aubin, Bump’s Republican campaign opponent, after being shown the auditor’s expense reports. “She’s out there a lot on state time currying favor with the unions in particular. She’s working the system, and I think it shows poor judgment on her part to be nickel-and-diming the state and not really thinking about the taxpayer at the end of the day.”

Bump used a state-leased vehicle for her trips around the state until August 2013, when she began using her own personal vehicle. For the period from January 2013 to August 2013, Bump’s expense reports indicate she used the state-leased vehicle 82 percent of the time for personal use. In April 2014, she reimbursed the state $3,700 for the personal use of the vehicle.