The portable credit and debit machines commonly used in restaurants are becoming a target for fraud scams, Toronto police say.

The portable nature of the devices means they can be brought right to the table. It also means criminals can swap the real device for a fake one if the server steps away for a moment.

Toronto police said they have seized several units in the GTA, which steal credit and debit card information through the chip reader, or through the card swipe strip.

Some of the devices are also equipped with blue-tooth technology, which means someone could be wirelessly stealing a PIN as the user inputs it.

Police say the problem is a relatively new one in Canada, but Toronto police Det. Ian Nichol said police have already found several different types of card readers, indicating more than one organized crime group may be involved.

"It involves a concerted effort of multiple individuals, all with different roles," Nichol said. "Different people have to utilize the cards. Some people manufacture the devices. Others are involved in the theft of the devices themselves."

Police said that grocery stores and food carts can also be targeted.

The bottom line, police said, is for restaurant owners to encourage staff not to let the mobile credit and debit machines out of their sight while the customer is completing their transaction.