We will all be at greater risk of theft when the debit and credit card limit rises to £100 next month, experts warn.
Currently anyone with a contactless card can spend £45 without being asked to enter a PIN.
But from October 15 that will rise 120% to £100, a move some experts have called a "thief's dream".
Card users will also be able to make £300 of transactions without entering a PIN, up from £130 now.
The changes are being brought in by the Financial Conduct Authority watchdog to make card use more convenient for customers and shops.
But the increase in card limits comes with an increased fraud risk, experts warn.
AJ Bell head of personal finance Laura Suter said: "Around half of all credit card transactions and two-thirds of all debit card transactions are contactless and this number will leap from October as people can use contactless for bigger items, like the weekly shop or filling up the car with petrol.
“However, while the move brings more convenience for some it also carries two big warnings. First, it is a thief’s dream, as they can take far more of your money in each transaction if you card is lost or stolen."
Suter added that there is a risk the increased card limit would encourage a slide into debt.
"The easier a card transaction is the less the consumer is actively thinking about how much they are spending, meaning it’s easier to rack up larger bills on a credit card," Suter said.
These warnings were also issued by Myron Jobson, personal finance campaigner at Interactive Investor.
He said: “The pandemic has sped up the transition to a cashless society, with card payments preferred over cash to reduce physical contact.
“However, upping the limit to £100 could exacerbate the problem of pickpockets or malicious individuals using lost bank cards to make as many transactions as possible before the account is blocked."
Victims of contactless card fraud are likely to be able to recover the lost money from their bank.
However, Jobson said it would take time and effort that many might struggle to find.
But others said the fraud risk was overplayed.
Financial experts at The Association of Accounting Technicians points out that the contactless increase from £30 to £45 came without a "corresponding increase in fraud".
