Internationally acclaimed concert organist Thomas Heywood guided children as young as six through the basics of the complex instrument on Saturday morning, ahead of his recital on Sunday.

Heywood also listened to two Warrnambool organ scholars play, while explaining the 2300-year history of the pipe organ to festival goers.

He described the church's 1890s-era pipe organ, a survivor from renowned builder George Fincham, as "very special" and "lovely" to play.

"The pipe organ sells itself, once people sit down and hear it and know how it works. It's a very complex and expensive machine," Heywood said.

"It would be between $1.5 and $2 million to buy today. Without a doubt it would be the most valuable musical instrument in western Victoria."

Warrnambool-based festival director Louise Keast said the sixth-annual festival had made the instrument and church loft accessible to the public.

"You don't have to know anything about the pipe organ to come and enjoy live music," Ms Keast said.

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