The credit crunch that has led many homeowners to default on their mortgage payments could be spreading to the credit card industry.

Credit card companies wrote off 4.6 percent of payments as uncollectible during the first half of 2007, which is 30 percent higher than the amount during the same period of 2006, according to the Financial Times. Citing data from Moody's, the report says that late payments from U.S. credit card holders also rose, and that the quarterly payment rate fell for the first time in four years.

"The combination of higher interest rates and a softer real estate market diminished the attractiveness of mortgage refinancings in which many borrowers reduced their more expensive credit-card debt by drawing on the equity in their home," Moody's said.

However, Moody's also said that it is unclear if the people defaulting on credit card payments are the same people defaulting on subprime mortgages.

Indeed, a combination of economic factors, including rising gasoline prices, could be leading some consumers to scale back their debt payments. "Consumer credit quality will continue to deteriorate as debt burdens and financial obligations rise, house prices continue to fall, credit standards are tightened, labor markets loosen modestly, and gasoline and other energy prices remain high," Scott Hoyt, an economist at Moody's Economy.com, told the F.T.