"Reverend Chris", as she is known, was ordained as the Hunter's first female Uniting Church minister in 1987 and will officially retire from her mental health role at the end of January.

The 59-year-old reflected recently on what had changed since she became mental health chaplain in 1990.

"I'd say our understanding of those with a mental illness, as a church and as a society, has come a long way," she said.

"In the last two decades a lot of prominent people have come out and helped reduce the prejudice attached to mental illness, especially depression."

Mrs Sheppard pointed to the example of ABC radio sports broadcaster Craig Hamilton, whose openness in dealing with bipolar helped destigmatise the disorder.

Applauding the Uniting Church for its acceptance of gay ministers, she hoped the next 20 years would erode more barriers.

"[The Church's] attitude to people with differing sexual orientation has made me proud," she said.

"We've actually asked the hard questions, like why are these gaps in our society."

While no longer the region's only female minister, Mrs Sheppard remains the only chaplain in mental health.

She said she had been privileged to meet a range of courageous people in the role, and will remain a minister with scaled-back duties including reading to school children.