By Leslie Eaton

WASHINGTON, Dec. 15 - Hector V. Barreto, the head of the Small Business Administration, defended his agency's response to the Gulf Coast hurricanes on Thursday on Capitol Hill, saying the agency had responded "quicker to this event than any in our history."

But amid evidence of growing backlogs and high rates of rejection in the agency's disaster loan program to businesses and homeowners, Democrats attacked his performance.

Senator John Kerry of Massachusetts, the ranking Democrat on the Senate Committee on Small Business and Entrepreneurship, issued a scathing statement accusing Mr. Barreto of offering small businesses in the gulf region "only hurricane-force spin," rather than real assistance.

Government officials and business organizations have complained that the agency has approved only a small number of low-interest business loans - fewer than 3,000 as of Dec. 13, according to the agency's own data. Almost 7,000 business loan applications have been rejected, and more than 27,000 are pending.

The backlog is far larger for homeowners who have applied for loans. The New York Times reported on Thursday that more than 175,000 applications - almost two-thirds of those the agency had received - had not yet been processed. More than 81 percent of the applications that have been processed were rejected.

To support his argument that the agency had moved quickly to respond to the hurricanes, Mr. Barreto said at a news conference that his agency had approved $1 billion in loans just as fast as it had in 1994, when the Northridge earthquake struck Southern California. But some critics of the agency contend that computer processing has improved significantly in the last decade, adding that the agency was slow back then, too.

As he has in the past, Mr. Barreto attributed the agency's high rejection rate to the high poverty levels in the areas struck by the hurricanes. "We're being as lenient as possible within the limits of our authority," he said of the loan programs.

Mr. Barreto said 80 percent of loan applications were from people who did not want to borrow money, but who had to be rejected by his agency before they could seek additional grants from the Federal Emergency Management Agency. FEMA referred more than two million families to Mr. Barreto's agency based on the incomes they reported when they registered for federal assistance.

Mr. Barreto made his comments at a news conference called by the chairman of the House Small Business Committee, Representative Donald Manzullo, Republican of Illinois. Critics of the Small Business Administration were actually dissatisfied, Mr. Manzullo said, because it offered loans, which must be repaid, rather than grants.

As for the speed of the loan process, Mr. Manzullo pointed to the agency's experience in New York after the Sept. 11 terrorist attacks, when businesses complained of a slow pace in lending "despite the fact that S.B.A. workers went out of their way to provide assistance."

But twice as many of those businesses defaulted on their loans as in previous disasters, Mr. Manzullo said, so if loans are made quickly "and you try to satisfy complainers, you have a huge default rate."

Representative Nydia M. Velázquez of New York, the ranking Democrat on the House committee, repeated her call for Mr. Barreto to resign. "This administration has failed small businesses across the country and particularly at a moment of crisis," she said at a separate news conference.

Ms. Velázquez criticized what she said was the agency's decision to change its computer system just before the hurricane season began, and also its promotion of a loan program offered through banks.

The United States Hispanic Chamber of Commerce issued a statement on Thursday defending Mr. Barreto, saying that "politically motivated attacks leveraged against Administrator Barreto undermine the hard work of a dedicated public servant."