The box, decorated with an emblem featuring a dove of peace, was dropped off in the parking lot at St. James Anglican Church in Croydon.
Its presence highlights the competition in Australia's commercial used clothing market and the diversion of goods from charities, the Sydney Morning Herald reported Tuesday.
"They must have put it there in the middle of the night. There was a little dove on it and makes it look like a charity," said St. James assistant minister Rev. Jon Guyer.
Commercial operators use networks of charity-style donation bins for used clothing, which are then exported, the newspaper said.
The box at St. James was removed after its owner, Chris Dankha of Dankha Pty Ltd, said it was either left at the church by mistake or moved there by one of his competitors.
Kerryn Caulfied, the head of the National Association of Charity Recyclers Organizations, warned Sunday private operators were obtaining second-hand goods, worth millions, normally directed to charities.