The Financial Conduct Authority (FCA) issued a "wake up call" to interest-only mortgage holders in May amid fears that up to 1.3 million customers did not have enough cash to pay their loans back.
Research conducted for the watchdog found that around one in 40 interest-only borrowers (2.5%) said they were not aware when they took out the deal that they needed a plan in place to repay the whole amount borrowed, not just the interest, and still had no strategy in place.
Some calls have been made for further work to be carried out to make sure borrowers were not victims of mis-selling.
But in a written response to a letter from Treasury Select Committee chairman Andrew Tyrie on the subject, Martin Wheatley, chief executive of the FCA, said there was "no evidence" to suggest that these one in 40 customers were concentrated in particular areas or profiles.
He said: "Were we to receive such evidence, we would consider a more targeted regulatory response, which could focus on specific lenders, regions or demographic profiles. In addition to our principle of communicating fairly with clients, we have clear pre-sale, point-of-sale and post-sale disclosure rules in respect of interest-only mortgages.
Interest-only mortgages, which allow borrowers to pay off the capital only when the mortgage term ends, have become much more thin on the ground since the boom years amid concerns about people not being able to pay back their debt.
Mr Wheatley said that complaints figures did not show any particular spike around mortgages. He said it was "impossible to rule out some instances of poor practice," in which case customers should complain, but the watchdog was not planning further work to look at historic sales practices.
Mr Wheatley said: "Instead we are focused on encouraging lenders and consumers to act now to mitigate the potential future consumer detriment."