WASHINGTON — Rates on 30-year mortgages edged up for a fourth straight week and to the highest level in two months, Freddie Mac reported yesterday.

The giant mortgage company said its nationwide survey showed that rates on 30-year mortgages rose to 6.28 percent, up from 6.24 percent last week.

That left the 30-year mortgage at the highest level since it stood at 6.30 percent the week of Dec. 15. Its rates fell as low as 6.10 percent in mid-January before rising again.

Economists believe that the path of mortgage rates this year will be heavily influenced by what the Federal Reserve does with the short-term interest rates. Fed Chairman Ben Bernanke in congressional testimony yesterday left the door open for further rate hikes.

Private economists are predicting that the 30-year mortgage rate will rise to between 6.5 percent and 7 percent by the end of the year.

"So far this year, fixed-rate mortgages have risen only slightly," said Frank Nothaft, chief economist at Freddie Mac, or the Federal Home Loan Mortgage Corp. "Long-term rates are only marginally higher than ... two months ago."

Rates on 15-year, fixed-rate mortgages averaged 5.91 percent this week, compared to 5.83 percent last week. One-year adjustable rate mortgages rose to 5.36 percent, compared to 5.34 percent. Five-year hybrid adjustable rate mortgages rose to 5.95 percent, up from 5.89 percent.

The rates do not include add-on fees known as points. The one-year ARM carried an average fee of 0.7 point last week; the other three categories averaged 0.5 point.