The bank has capped the amount customers can send to cryptocurrency exchanges to £1,000 per day. The 30-day limit is set at £5,000.
Santander to limit crypto buying over fraud spike
Unveiling the move, NatWest said the decision was made to increase customer protection against losing "life changing sums of money" to crypto criminals.
According to the bank, £329m was lost last year to scammers hiding behind fraudulent cryptocurrency schemes industry-wide.
Cryptocurrency investments can be made through legitimate exchange platforms, which let customers buy, sell or exchange cryptocurrencies for other digital currency or traditional currency.
However, criminals play on a lack of understanding of how cryptocurrency markets work and their unpredictability to encourage investors to transfer money to accounts set up in the customer's own name by the criminal or by the victim, under duress from the criminal.
Men over 35 are most at risk due to them being more willing to take on risky investments, according to NatWest.
Treasury sets out plans to regulate crypto
The cost-of-living crisis is also having an impact, with promises of high returns used by criminals to entice investors.
Stuart Skinner, head of fraud protection at NatWest, said: "You should always have sole control of your cryptocurrency wallet and nobody else should have access. If you did not set the wallet up yourself or cannot access the money then this is likely to be a scam.
"We have seen an increase in the number of scams using cryptocurrency exchanges and we are acting to protect our customers."
Cryptocurrency is not protected by the UK's Financial Services Compensation Scheme and most are not regulated by the Financial Conduct Authority, although the Treasury has recently set out plans to bring cryptocurrency into regulatory purview.