Bishops are not unfamiliar with microphones " countless confirmation services see to that " but the particular pulpit Robert Forsyth will be ascending this Sunday will put him in the homes of tens of thousands of Sydneysiders.

Sydney radio station 2CH has asked the Bishop of South Sydney to fill in for Sunday night regular Ross Clifford as he takes annual leave.

And Bishop Forsyth is relishing the opportunity to address this new audience.

"You’re talking to thousands of people who might be lying at home listening and you’re talking to them personally, and that’s why I love it," he says as he prepares for his first show this weekend.

"It’s a bit of fun really, but it’s a really demanding environment. You’ve got to talk and imagine that one person listening," he says.

The Bishop believes that despite all the technological advances of the last decade, radio continues to be one of the most engaging media.

And Robert Forsyth should know " he's no stranger to the microphone.

Prior to coming to the Sydney Diocese he spent two years hosting talk-back radio in Adelaide.

“It was a long time ago " I was interviewing Mother Therasa; the Falklands War was on," he says, laughing.

"I'm probably not as nice now as I was then. I feel I’m a bit grumpier now," he says ruefully.

Each Sunday night on 5DN he would listen to the lives of average Australians and offer a Christian perspective.

In the "90s Sky News host Leigh Hatcher was Bishop Forsyth's producer, and he was capable of operating his own radio panel.

But today, with studios looking more like the interior of passenger jet cockpits, he's happy to allow someone else to push the buttons.

"Fumbling seems to be very unprofessional " and in case you're wondering, it's a quarter to five and a balmy 22 degrees in my office," he says, dropping into his best "radio' voice.

But, jokes aside, Bishop Forsyth welcomes the opportunity to put aside the Episcopal purple to engage with Sydney's moral debate.

"It does put you in a different mode of relationship," he says.

"I think friends should understand that radio is not like running a church meeting and you must be much wider in the type of people you will listen to and talk to. You can give space to people you might not otherwise consider to be ‘sound’."

"But it's all part of engaging in the great debate."

Listeners can tune into Bishop Forsyth taking the temperature of the city's listeners from 9:00 PM -12:00 AM at 1170 on the AM dial for the next two Sundays.