Subprime mortgage payments have taken a backseat to credit card payments, according to one new study.

Borrowers with credit scores under 621 are more likely to become 30 days past due on their mortgages than on their unsecured bank credit cards, according to the study from Experian announced Wednesday. But borrowers with credit scores above 680 still pay the mortgage before bank card debt.

The report, which was conducted using "a sophisticated portfolio management tool," noted subprime mortgage delinquency has increased at a 13.2 percent rate in the past four years, with the West increasing 15.3 percent -- the sharpest of any region. During that same period, subprime mortgage lending grew 58 percent compared to 137 percent for subprime bank card lending.

"The current marketplace debate and increased visibility on subprime lending led us to examine historical consumer payment trends to see if they have shifted," Kerry Williams, president of Experian Information Solutions group, said in the statement. "Our data revealed that many consumers in the subprime segment have adjusted their payment patterns in order to better manage their personal finances."

Between 2005 and 2006, Experian said subprime mortgage balances jumped 8.8 percent, while overall mortgage balances increased just 3.3 percent.

"It is prudent for lenders to explore improvements in decisioning process and tools to counter recent market trends," Williams added.