The journalist and television presenter said some companies were using his image and the name of his company to sell “scams” through adverts on Facebook, which he said his company does not use.
Mr Lewis said some people had already lost thousands of pounds in a binary trading scam.
The Financial Conduct Authority has this week warned that UK consumers are increasingly being targeted by binary options investment scams.
These are a form of fixed-odds betting which typically involves whether an event will happen or not, such as the price of a particular share or asset going up.
If the investor is correct then they “win” and would see a return on their investment but if they are wrong they lose their full investment.
Of the scams leveraging his name and image to hook in investors, Mr Lewis said: “Perhaps the most disgusting one is a cloud trading scheme that pretends I’ve invested half a million pounds into it and I’m saying it’s the best possible thing you can do with your money.
“It is a con, it is a scam, it’s about binary trading, it is a brilliant way to lose money.
“Do not touch it, do not sniff it, do not smell it, do not go near it. It has nothing to do with me.”
The FCA, which said binary options are not currently regulated, states on its website: “Binary options traders often advertise on social media – the ads link to websites that are well-designed and professional looking.
“The firms operating the scams tend to be based outside the UK but often claim to have a UK presence, often a prestigious City of London address.
“Scam firms may manipulate software to distort prices and payouts – they then suddenly close consumers’ trading accounts, refusing to pay back their money.”
The Gambling Commission and the City of London Police have also issued warnings about binary trading.
Scott Gallacher, a financial adviser with Rowley Turton, said: "I have not come across them but I am sceptical of all of these things. For me they are not investments, they are just speculation or gambling."