Homeowners could be set to face an additional mortgage bill on top of any rises to the standard variable rate (SVR).
According to new research from Which?, customers may face an extra £300 million in repayments over the next 12 months.
The investigation revealed 70 per cent of those questioned are worried about an interest rate increase, while 14 per cent are finding it difficult to keep up repayments.
It was found that a rise in such costs of just £50 a month would result in 41 per cent needing to restrict spending and 20 per cent having to reduce savings.
Peter Vicary-Smith, chief executive of Which?, noted: “Our advice to anyone struggling with their mortgage repayments is speak to your lender straight away.”
Mr Vicary-Smith said SVR rises are due to a lack of competition in the home loan market at present, while the government has also failed to promote competition in the sector.
He added the Financial Services Authority – which is the regulator of the UK’s financial services industry – should make a greater effort to shield consumers from unjustified interest rate escalations.