According to the chancellor, banks are "taking too long" to pass along interest rate increases to savers.
Jeremy Hunt claimed that the "issue that needs solving" was particularly affecting users of instant access accounts.
While banks seem to be moving more slowly to increase returns for savers, they have been quick to pass along higher interest rates to mortgage customers.
Savings and mortgage rates are not "directly linked," according to the trade association for the banking industry.
However, Mr. Hunt claimed that he brought up the subject last week with banks in "no uncertain terms.".
He complained that it was taking too long for savers to benefit from interest rate increases and pointed out that those with instant access accounts were particularly affected. People who have fixed term, fixed notice accounts are more frequently subject to rate increases, according to Mr. Hunt.
According to the most recent data, the difference between average mortgage and savings rates has grown since December 2021, when the Bank of England first began raising interest rates in an effort to slow the rate of increase in consumer prices.
According to financial information company Moneyfacts, the difference between the average rates for two-year fixed mortgages and easy access savings accounts, which are the most popular savings accounts, was 219 percentage points at the time.
The difference between the average two-year mortgage deal and the savings rate on Monday was 3 points, or 623%.
Although the difference has grown since interest rates were first raised, it is still smaller than it was in December 2022, when it was 4 point 24 percent.
Interest rate increases typically boost net interest income, which is the difference between the amount that banks can raise borrowing costs and the amount of interest they pay out on deposits, increasing banks' profits.
Savings and mortgage rates "aren't directly linked and therefore move at different times and by different amounts," according to UK Finance, the industry trade group for the banking sector.
It stated that "Savings rates are driven by a number of factors, not just the Bank of England's Bank Rate." One important factor is whether a person wants instant access to their money or can deposit money for a longer period of time.
But in recent months, members of the Treasury Committee have frequently brought up the concern that savings rates have not increased in step with rising mortgage costs.
MPs questioned the CEOs of NatWest, Lloyds, HSBC, and Barclays, four of the largest banks in the UK, in February regarding how generous their savings rates were.
The banks argued at the time that savers had access to a variety of competitive offers, but they have since come under fire after this month's description of Lloyds' interest rates on savings as "measly.".
On Wednesday, the chancellor will meet with regulators to talk about inflation and the way that changes in interest rates are passed on to consumers.
When the BBC questioned Mr. Hunt about why he hadn't brought up the subject of savings returns earlier, the Treasury responded that Mr. Hunt was in "regular contact" with banks.
Reporting by Peter Ruddick in addition.
