Police spokesperson Captain Stephen Thakeng said that in one incident a victim was robbed of R500 000 when he bought a non-existing item on the online classified site.
"More arrests are imminent, so that is why we wanted people to be aware of this."
Gumtree is an online classified website which allows people to advertise their unwanted items to potential buyers.
"These advertisements are placed all over the country to cheat unsuspecting buyers. Cases of fraud were registered and some of the suspects will be appearing in Hoopstad Magistrate Court facing charges of fraud."
Thakeng said that in a case that dates back to 2012, various advertisements were posted on Gumtree stating that the suspects were selling front loaders, motor parts, industrial vehicles and truck parts that did not exist.
"The alleged fraudsters placed different companies to be situated in different towns all over South Africa. In most incidents contact persons on those advertisements were Belinda De Beer, Samantha De Beer and Malcolm De Beer," he said.
"When suspects are cornered about the business, their response will be that the business has been liquidated and another business will be placed on the social media with a different company name."
Thakeng said that potential buyers were advised to be careful when buying through social media and ensure that they receive the product before making payments to unknown people. He urged victims of these scams to come forward.