Apple co-founder Steve Wozniak says he has concerns about ride-sharing multinational Uber​ becoming a monopoly and forcing down the wages of its drivers.

Speaking on the sidelines of the state government's "Future Transport" summit in Sydney, Mr Wozniak said it was important that there were four or five competitors to Uber, and in the United State he took ride-sharing rival Lyft​ when he could.

"I do have concerns about Uber becoming a monopoly. Like a lot of people, I have some distrust of Uber and how their drivers don't really realise necessarily at first that they aren't really making much money, maybe losing money on the wear and tear of their cars," he said on Monday.

"Uber will push their workforce down to the absolute lowest minimum wage that they can get away with. That's how I think of Uber – not really nice thoughts."