Caroline Corby said it was of “significant concern” to her, adding that the approach to recruitment will change.
Ms Corby also outlined how the board, which assesses whether serving prisoners in England and Wales are safe to be released into the community or moved to open conditions, had suffered a “loss of confidence” following the John Worboys case.
She said it was hard to measure if members were more risk-averse following the case, although she noted that the release rate was usually around 49% but decreased to about 42% in the immediate aftermath and has since increased to 46%, with more adjournments and deferrals.
The Parole Board sparked huge controversy in January by ruling that Worboys, known as the black cab rapist, was safe to be freed after around a decade behind bars.
The board’s release direction was quashed by the High Court in March and changes were made, including a transparency drive over its decision
Speaking to the BBC, Ms Corby said of the board’s diversity: “I am a little bit concerned about this.
“Of our 240 members, 13 currently have a BAME (black, Asian, and minority ethnic) background and I want to do better than that.”
She added: “At the moment we have no black Parole Board members and that’s of significant concern to me. But in terms of addressing this issue, we’re very keen to have as many people with a BAME background apply to us as possible.
“We have learnt lessons from our last recruitment round because we actually had the same objective and we weren’t successful so I am determined to learn lessons from last time around.”
Asked why, Ms Corby said there were not enough applicants from BAME backgrounds and those who did apply did “very poorly” in the first two stages of the five-stage process for “reasons we don’t entirely understand”.
She added: “But I think there must have been some kind of unconscious bias in those processes. We’re not going to have those processes next time around.”
On the impact of the Worboys ruling, Ms Corby said: “It was obviously a very difficult period for the board.
“We saw the departure of our previous chair in difficult circumstances, the board was subject to unprecedented amount of publicity, the like of which we haven’t experienced before, and I think there was a loss of confidence amongst ourselves a little bit, perhaps a loss of confidence in the wider public and that was something I am very keen to repair.”
Mark Leech, Editor of The Prisons Handbook for England and Wales said: “Its absolutely right the Parole Board recognise this huge gap between its membership and the diversity of service users whose release they are considering – justice demands understanding.
“The Parole Board has just 5% of its membership from BAME backgrounds, yet over 26% of the prison population identify as BAME – what does that say for justice?”