Cleaners are normally seen and not heard, if they are seen at all. They come into workplaces as staff are leaving, empty bins and scrub toilets clean, then disappear into the night: The Keyser Söze of the working world.

On the corner of Sussex and Market Street a small group is bucking the trend. There are only eight protesters but with three megaphones, and one bloke beating a plastic container, they are making plenty of noise outside the Commonwealth Bank offices.

“What the hell has the Commonwealth Bank got to do with cleaners?” you are probably wondering. We were baffled until we spoke to Alex Morales, an organiser with the United Voice union. The Commonwealth Bank owns a bunch of shopping centres and the union wants the cleaners there to get the same conditions that cleaners in CBD buildings have fought for and won. They’ve already been protesting outside Westfields and Stockland for the same cause.

Morales hands me a leaflet. It notes the bank’s $6.835 billion profit last year compared to a cleaner’s $34,000 before tax. “We only started doing this kind of action in the last two weeks,” he says. “This is the last resort.”

Office workers hurry past as the protesters yell out their complaints to the tune of Waltzing Matilda. The singing isn’t exactly easy on the ears. A few passers-by grab a leaflet. Hopefully the campaign has some results soon. These cleaners can’t afford to give up their day job.

Learn about the campaign here