By Sarah Toyne
BBC News Online personal finance reporter
Phishing scams are becoming a growing problems
NatWest has become the latest target for an e-mail scam, which tricks customers into giving away confidential bank details, BBC News Online learns.
The internet scam, known as "phishing" has recently targeted Barclays and Lloyds TSB customers.
News Online readers reported they received suspect e-mails on Friday asking them to verify their banking details.
The scams originate from Eastern Europe - and are the first part of a two-tier scam which has emerged in recent months.
The e-mail says information is needed to verify a customer's e-mail address.
They are asked to click on a website link and enter their NatWest login ID, password and pin into a pop-up box.
The site, which was still operational on Friday afternoon looks authentic, and could easily trick customers into handing over their details.
The e-mail adds: "This is done for your protection - because some of
our members no longer have access to their e-mail addresses and we must verify it."
Experts say the phishing scams are indicative of a growing trend of fraudsters targeting vulnerable consumers.
A spokesman for NatWest said: "We are aware that some internet users have been targeted by fraudsters with this e-mail asking for them to confirm their e-mail address by entering their NatWest online banking security details.
"We never ever ask customers to provide this kind of information and we have put in place immediate processes to combat the fraud."
The bank is advising anyone who feels they may have been affected to contact it immediately, and said that people who had lost out would be compensated for losses.
It has recently emerged that phishing scams are the first part of a two-tier scam.
The second stage, known as "money transfer" or "job offer scam" involves advertising for British people with UK-based accounts to act as agents to transfer money overseas.
As the people perpetrating the fraud are located outside the UK, they cannot transfer money directly out of their victims' online accounts to their own accounts abroad - and so need an intermediary.
In effect, these people are unwittingly being used as money "mules," and they could see themselves prosecuted by the police.
Barclays told BBC News Online that a very small number of its customers had fallen for this "job offer" scam - and it is warning people to steer clear of any similar job offers.
Lloyds TSB customers were targeted by e-mail phishing scams in September, but the bank said no fraud had been committed.
It also said that none of its customers had alerted it to the job offer scams.
Anyone who has concerns can contact NatWest's helpdesk on: 0845 6050789.