The deregulatory policies of the Reagan administration helped contain the savings and loan crisis, former Treasury Secretary Donald T. Regan is telling skeptical congressional Democrats.

"I think the thrift industry would have gone into the tank sooner and may have never emerged," Regan told the House Banking Committee at the first in a series of hearings on the causes of the S&L mess.Regan, who was Treasury secretary from 1981 to 1985, said that after interest rates soared in the early 1980s it became clear that a financial business confined to taking deposits from savers and lending the money to homebuyers could not survive.

He said he had favored giving thrifts the same investment powers as commercial banks but had opposed the broader deregulation in some states that had given thrifts non-bank powers.

The committee also heard on Monday from Richard T. Pratt, who served as the nation's top thrift regulator from 1981 to 1982. Pratt defended his decision to allow S&Ls to hide their losses with accounting techniques.

Pratt said when he took office, nearly every S&L in the country was technically insolvent because soaring interest rates had drastically cut the value of their low-interest, fixed-rate mortgages.