Research carried out by the bank has found social networking sites are the most commonly targeted by scammers.
Facebook's buying and selling site was the most reported for scams in Britain, according to data collected between September 1 and November 22, followed by Instagram.
The report comes as shoppers are expected to flock online for Black Friday, one of the busiest online shopping times of the year, to take advantage of discounts and sales ahead of Christmas.
eBay is also popular with scammers and was ranked third, with advertisement and community website Gumtree in fourth, NatWest said.
NatWest research has found social networking sites are most targeted by scammers ahead of Black Friday
More than 1,000 scams were reported on Facebook Marketplace between September 1 and November 2, research has shown. Pictured: Facebook CEO Mark Zuckerberg
The research found common scams on the social networking sites include advertising goods at heavily discounted prices.
The popular scam involves the seller asking the buyer to pay via a bank transfer prior to the product arriving.
Jason Costain, Head of Fraud Prevention at NatWest, said: 'Don’t let fake influencers or sellers steal your Christmas by sending them a payment for presents you will never receive.
'It is the fraudsters' favourite time of year, so make sure you're on your guard when buying goods you’ve seen on sites like Facebook Marketplace and Instagram.'
More than 1,000 scams were reported on Facebook Marketplace over the period between September 1 and November