The Massachusetts Sex Offender Registry has lost track of more than 1,700 convicted sex offenders, according to a state audit released on Wednesday.

The report from the office of Auditor Suzanne Bump concluded that the registry lacks adequate policies and procedures to ensure that sex offenders are promptly classified. As a result, the public has no way to know if some potentially dangerous sex offenders live in their communities, while the risk that those individuals will commit new crimes increases, Bump said.

As of February, the registry did not have current addresses for 1,769 people who were convicted of sex crimes between October 1996 and January 2017, and have either been released from prison or are on parole, according to the audit. Of that total, the registry has yet to classify the threat level of 936 individuals, including more than 300 that had committed sex crimes against children.

State law requires convicted sex offenders to register with the sex offender board and update their information annually, including any changes to their address. The board then classifies them as Level 1, Level 2 or Level 3. Level 2 and Level 3 offenders are considered to be most at risk of reoffending.

Bump called the findings "disturbing."

"What we found was an agency that really wasn't able to meet its mission of properly classifying or tracking individuals who were supposed to be registered sex offenders," said the Democrat. "That left police officers, the public and past victims without the knowledge ... as to the whereabouts of Level 2 and Level 3 sex offenders."

Failure to register or report changes in address can result in arrest and imprisonment.

Felix Browne, a spokesman for the state's Executive Office of Public Safety, said while the registry is responsible for classifying sex offenders, it lacks the authority to track down people who fail to register or notify law enforcement of any move.

The registry currently has records on nearly 22,000 "active" sex offenders, according to the report. About 13,000 of those were believed to be living in Massachusetts, while the rest had either moved out of state, been deported or returned to prison.

In a written response to auditors, the registry cited laws and regulations that hampered their ability to classify the 936 individuals, including a requirement that offenders be given notice before the classification process can begin.

"Offenders who are in violation are quite often incapable of being provided with the requisite notice to proceed with their classification," the registry said in a statement.

About 50 of the unclassified sex offenders were believed to be dead, and it was believed about 270 others were either living outside of Massachusetts or had been deported, the statement added.

The audit left out some critical facts about court rulings that established new guidelines for classification, Browne said.

A 2015 decision by the state's highest court required a standard of "clear and convincing evidence" in classifying sex offenders and resulted in 378 cases being returned for reclassification hearings.

The recommendations made in the audit included that the registry make a more concerted effort to get sex offenders classified before they complete their prison terms, and work closely with other state agencies, such as the Department of Revenue and the agency that administers welfare benefits, which could share more information about where people currently live.