"It was located at Town Pt, 1.8km north of the Kaituna Cut."
The barge was travelling between Maketu and Motiti Island when the digger fell off the back and into the sea.
Mrs Balvert-O'Connor said local sources believed it was an excavator heading over to Motiti Island.
Maketu chief fire officer Shane Beech said the lost digger was one of the the region's quirkiest tales.
"People do know about it but it all happened quite a few years ago so no one really knows what happened," he said. "We've known generally where it is located, it's quite a good fishing spot."
Maketu commercial fisherman Butch Waterhouse said the digger was lost at least five years ago.
"I wouldn't have a clue how it got there. I don't even know who owned it. People do know it's there. It's one of our best-kept secrets. Maybe not anymore, though" he said.