Defense attorneys say the Alameda County Sheriff’s Office may have illegally recorded attorney-client privileged conversations through a software glitch in Santa Rita Jail’s in-house phone system, in what is the latest allegation of eavesdropping against the department.

Sheriff’s officials denied the new accusation. But on Tuesday, Alameda County Public Defender Brendon Woods plans to ask a judge to formally bar the department from the alleged practice of recording privileged conversations, which is already illegal under California law.

“My biggest concern is that they are recording, that it’s being kept somewhere, and they have the ability to access this when they want to,” Woods said Monday evening in an interview with The Chronicle.

Ray Kelly, a spokesman with the Sheriff’s Office, said the department has ensured no illegal recordings are taking place, and that suggestions to the contrary are false.

“They are absolutely denying that any of those things occurred,” Kelly said of sheriff’s officials familiar with the phone system’s upgrade.

The allegations come nine months after Alameda County Sheriff’s Sergeant James Russell was charged with four felony counts of eavesdropping for allegedly recording privileged conversations between juvenile suspects and their public defender.

Russell is currently on leave, and his charges are still pending in Alameda County Superior Court.

The new claims center around a phone system for “non-contact” visits at Santa Rita Jail in Dublin. Non-contact discussions take place in booths separated by glass, with a handset and cord attached to both sides.

In the past few weeks, the phones have included a recorded statement informing visitors and inmates that the conversations are being monitored, recorded and shared with the District Attorney’s Office, Woods said, recounting the experiences of at least three attorneys.

The recording instructs callers to hang up if they do not agree to the terms.

Jailhouse conversations between an inmate and family or friends are legally monitored, and there is no expectation of privacy. But discussions between attorneys and clients are protected by law, and the jail’s phone software includes safeguards designed to protect this tenet, according to sheriff’s officials.

When public defenders made sheriff’s officials aware of the statement about phone calls, the attorneys were assured that their conversations were not being recorded.

One public defender described hearing the recorded statement when interviewing a client on June 15, according to a draft of Woods’ motion provided to The Chronicle. She said she was told that the conversation had not been recorded.

However, when she returned to meet with the same client on June 25, a deputy told her she could not conduct the interview in that location because the software system would record and monitor all inmate calls, and that staff did not know how to disable this feature, the motion states.

Kelly acknowledged that the phones had included the recorded warning statement due to a glitch in a system upgrade. The message has since been removed, he said.

But Kelly denied the alleged account of the deputy who said employees couldn’t turn off the recording portion of the phones.

“They’re confident that those calls were not recorded,” he said. “Our people have been working over the top to make sure that there is not any attorney-client privileged conversation recorded.”

Kelly added that in an abundance of caution, sheriff’s officials have sometimes moved attorney-client interviews to a different visiting center to ensure the conversations aren’t recorded.

Woods on Monday said he’s particularly concerned that the Sheriff’s Office is using the Global Tel Link phone system, which is associated with accusations of phone calls being improperly recorded between Orange County jail inmates and their attorneys.

In Woods’ earlier complaint involving Russell, he alleged that the sergeant’s body camera captured him discussing recording youths’ conversations with their attorney. Sheriff’s officials said Russell’s alleged conduct was an isolated incident, and that staff has been retrained on existing policies.

Alameda County Superior Court Judge C. Don Clay blasted the Sheriff’s Office over the allegations but stopped short of issuing an order to stop eavesdropping. Clay at the time said he may reconsider if he saw evidence that the problem was more widespread.

Megan Cassidy is a San Francisco Chronicle staff writer. Email: megan.cassidy@sfchronicle.com Twitter: @meganrcassidy