It has turned into a cash cow for its wealthy owners who include billionaires Jack Cowin and Brett Blundy, delivering almost $20 million in payouts to them in a little over a year.

But the two-decade grip that BridgeClimb, the business founded by entrepreneur Paul Cave, has had on leading tens of thousands of people over the southern arches of Sydney Harbour Bridge every year – at up to $378 a pop – is about to be tested.

Roads and Maritime Services, the government authority that oversees the Australian landmark, has put out to tender the "Sydney Harbour Bridge tourist climb business", which includes a museum within the south eastern pylon.

"Roads and Maritime are encouraging innovative new tourism experiences whilst seeking to achieve the best value for the people of NSW," it said in its request for expressions of interest from the private sector.