john j. o’brien, the reclusive state commissioner of probation, is coming out of his shell.

Faced with two reports suggesting that spending at his agency is excessive, O’Brien is suddenly talking. Well, not talking exactly, but sending out emails and letters through his spokeswoman denying many of the accusations and suggesting that his agency is actually understaffed.

In one email, O’Brien says the ratio of offenders to probation officers in his department is 167 to 1. Even excluding less involved administrative cases, O’Brien says, the ratio is 103 to 1, well above the caseloads recommended by the American Probation and Parole Association.

O’Brien also boasts that his agency is bringing in $23 million in annual probation supervision fees, requiring offenders to do $377,000 of community service work each month, and running an electronic monitoring program that is saving the state $80 million a year.

It’s a far cry from his agency’s usual response to requests for information, which is to ignore them.

The probation department has been under fire. Problems started in early December when a former accounting clerk at the Lawrence District Court’s branch of the probation department was arrested for allegedly stealing $2 million over three years. Then came reports by two different groups indicating that probation spending is rising at a much faster pace than outlays for other corrections divisions and court units. Probation is a corrections agency but is located administratively within the state’s Trial Court. Some officials in the state’s correction system would like to move probation into the executive branch. Patrick administration officials declined comment.

The two probation reports did not speculate about the cause of the agency’s budget growth, but the department is widely viewed on Beacon Hill as a patronage haven for the Legislature. The wives of Reps. Thomas Petrolati and Michael Costello, both members of House Speaker Robert DeLeo’s leadership team, work for the department, as does the son of former Senate President William Bulger.

Like most other parts of state government, probation has seen its budget cut in the past two years. But lawmakers have repeatedly softened the blow by overriding vetoes of probation spending by Gov. Deval Patrick, giving the department special appropriations, and insulating the agency from cuts by court officials. The Legislature, for example, gave probation $4.5 million last October to stave off layoffs.

The Court Management Advisory Board, a group of businesspeople working on a broad review of the trial court system, discovered that probation spending was out of whack compared to the rest of the court system. Board data obtained by CommonWealth indicate that the caseload of probation increased only 2 percent between fiscal year 2005 and fiscal year 2008, while spending went up 17 percent. The data also show the number of probation workers increased 10 percent between July 2005 and July 2008, rising from 2,005 to 2,200.

Michael Keating, who heads the advisory board, confirmed that the numbers are accurate. He said the probation budget’s growth was distorting the overall Trial Court budget and raised questions about the Legislature’s decision to insulate probation from court supervision. To help court officials manage budget cuts, the Legislature last year gave the officials the power to transfer funds between court accounts. But lawmakers specifically exempted probation from that directive. The Legislature has also limited the power of court officials to control probation hiring.

“From a management point of view, to take an important part of what has been designated a judicial function and insulate it from the person running the Trial Court doesn’t make any sense,” Keating said. “It’s bad management. It’s one of the things that has to be corrected.”

In an interview with CommonWealth, Margaret Marshall (also see Conversation, Page 76), chief justice of the Supreme Judicial Court, said the ability to transfer funds between accounts within the court budget is needed. She said she didn’t know whether funds would be transferred out of probation if court officials had that power.

Probation spending also surfaced in a report issued by The Boston Foundation last month on the rising cost of the state’s corrections system. The report said corrections spending overall had risen faster in Massachusetts than the budgets of almost any other state service. It said the Department of Correction budget, adjusted for inflation, had increased more than 12 percent between 1998 and 2008, while the county sheriffs’ budget went up 20 percent. Probation, the report said, went up 163 percent.

O’Brien, in his emails and letters, called the 163 percent figure “wildly inaccurate.” He said the Boston Foundation report compares 1998, when probation spending was marbled into line items for each court, to 2008, when spending was consolidated under his control.

“Simply put, the comparison of the FY1998 probation budget to the FY2010 budget is to compare apples to oranges,” O’Brien wrote.

Leonard W. Engel, a senior policy analyst at the Crime and Justice Institute and the author of the Boston Foundation report, said he tried to adjust for the budgetary changes by reducing the actual FY2008 number by $85.6 million to reflect the money earlier contained in court budgets. Engel said he was startled at the increase but checked the figures repeatedly and believes they are accurate.

O’Brien did not address the Court Management Advisory Board’s numbers directly, other than to say that part of the increase in spending can be attributed to the $2 million approved for the electronic monitoring of offenders using a global positioning system. He said the annual cost of electronic monitoring an offender is $3,380, compared with incarceration costs of $48,000. He called the system the most comprehensive in the nation, covering 1,800 offenders and saving the corrections system more than $80 million.

O’Brien also said his agency collects $23 million in probation supervision fees, up from $6 million in 1998, and has offenders perform 52,000 hours of community service work each month, which he valued at the minimum wage of $7.25 an hour, or $377,000.