As interest rates rise, the number of homeowners refinancing their mortgages continues to surge.

Australian Bureau of Statistics figures show $17.9 billion worth of loans were switched to a different lender in July, following a record $18.2 billion in June.

A survey by digital property exchange PEXA shows many owners are taking advantage of the tactic of banks to offer better interest rate deals only to new customers.

Its survey of 519 homeowners who recently refinanced, or who intend to in the next two years, shows their main motivation is to save money.

More than one million Australians refinanced last year which on average resulted in a 0.4 percentage point reduction in their mortgage interest rate, which equates to a saving of about $1,524 a year on a $610,000 loan.

The savings for owners switching to a new lender was 0.5 percentage points, while those refinancing with their existing lender only achieved rates about 0.1 percentage points lower.