Over half of homeowners in the South East are concerned, followed by the South West at 49%, according to a Halifax survey.
Across the country, one in ten mortgage holders (13%) said they would find it difficult to afford their monthly mortgage repayments if it rose £50. A third would find it hard to stretch to an extra £100.
Rate rises are more likely to worry women, those in the 35-44 age bracket and families with children. Respondents with variable rate mortgages at 57%, were far more worried than those on a fixed rate.
To find the extra cash for a £100 rise in mortgage payments, a third of mortgage borrowers said they would have to cut spending on essentials such as food, energy, clothing and insurance.
This rises to 39% for Londoners and those living in Wales.
Craig McKinlay, mortgages director at Halifax, said: “Speculation of a potential rate rise has been high up on the news agenda for some time now so it is perhaps surprising that the majority of homeowners are not concerned about this.
He continued: “While responsible mortgage lenders take into account potential rate increases as part of the affordability checks in the mortgage application process, the way in which people manage their remaining disposable income will be a key factor in how well they can adjust to any changes in rates.”
