A consumer group said it wants to see clear industry progress to tackle bank transfer scams, where people are tricked into transferring money directly to a fraudster.
Which? said that, a year after it made a "super complaint" to regulators about the issue, on September 23 2016, it is concerned that people have continued to remain at risk from bank transfer fraud.
It wants to see what is being done to tackle the problem, which can see fraud victims losing "life-changing" sums to scammers.
The Payment Systems Regulator (PSR) is due to give a progress update in November.
Which? raised concerns that, unlike many other payment methods, victims conned into transferring money by bank transfer to a fraudster generally have no legal right to get their money back from their bank.
The consumer group said its research suggests the overall scams figure of losses is likely to be huge - in the first two weeks after launching its online scams reporting tool in November 2016, more than 650 people told Which? about losing a total of more than £5.5 million to bank transfer scams.
Responding to the super complaint in December 2016, the PSR set out an initial action plan.
The regulator said banks should look at what information could be shared to help victims recover their cash. A common approach to best practice standards should also be developed, which both the victim's bank and the bank that receives the money should follow when responding to reports of scams, the PSR said.
But the regulator stopped short of proposing changes to make banks liable for reimbursing victims of such scams.
In an update on Friday, the PSR said: "Since December we've looked at a number of issues in greater detail and have continued to work hard to find a way to reduce scams and the impact they have on victims.
"We have worked closely, and continue to work closely, with the industry, Which?, the FCA (Financial Conduct Authority), and many others.
"This November we will publish a report highlighting progress against the measures we set out, as well as our thoughts on what should happen next."
Which? wants to see clear progress on measures including robust guidelines for financial institutions to support victims of scams and banks showing how they will improve data sharing to improve their response to bank transfer scams.
Gareth Shaw, a money expert at Which?, said: "A year on from our super complaint, consumers have continued to remain at risk from bank transfer fraud with many people losing life-changing sums of money to scammers.
"The regulator must now clearly set out what progress has been made by banks, and what more they must do to ensure consumers who are tricked into making a payment to a fraudster are not left out of pocket.
"Data sharing between banks and best practice standards must be agreed and adopted across the industry to make sure consumers are protected."