The Maryland House of Delegates, nearing approval of stringent new regulations for state-chartered savings and loans, rejected a proposal today that some members said would give those thrift associations the legal ammunition to attack the reforms.

House members were debating a series of routine amendments to the S&L reform legislation, one of the most politically sensitive bills of the 1986 session, when House Speaker Benjamin L. Cardin (D-Baltimore) and another delegate proposed additional language prohibiting any of the new regulations from causing "undue hardship" to Maryland's thrift industry.

Several House members, led by Del. Dennis C. McCoy (D-Baltimore) pounced on the proposed amendment, saying the new language would supply savings associations with a novel legal argument they could use to challenge all of the new regulations.

In recent weeks, as the S&L regulatory bill has worked its way through the legislature, several savings and loan executives and industry lobbyists have criticized the proposed reforms as too harsh on their associations. The bill would give sweeping new authority to the director of the state Division of Savings and Loan Associations and would mandate civil and criminal penalties against any state-chartered thrift that violates the new lending and investment rules.

The new authority is needed, proponents say, to prevent a recurrence of the state's present savings and loan crisis, in which several thrifts have failed and depositors' funds have been frozen. A state investigator determined this year that regulatory collapse, plus greed on the part of some S&L owners, led to the crisis, now in its 10th month.

Del. Michael R. Gordon (D-Montgomery), who opposed Cardin's amendment, asked, "Couldn't the industry use this language to defend itself from regulation?"

Del. John S. Arnick, a Baltimore County Democrat and a sponsor of the amendment, acknowledged that the new language provided "an argument that could be raised" and agreed to withdraw that section of the amendment.

However, when the Cardin-Arnick amendment came up for a final vote, McCoy and Gordon continued to hammer away at the remaining language. "This amendment can cut either way for more restrictive review of the industry or less restrictive review," said Gordon. "It's a vehicle for the industry to challenge the regulations it doesn't like."

Then, breaking Cardin's usually firm rule over the House, delegates defeated the amendment, 57 members voting against and 47 -- including the speaker and several of his committee chairmen -- voting in favor. Thirty-seven did not vote.

Delegates also passed, over Cardin's objections, another amendment that strengthened one provision of the reform bill. The House voted 65 to 45 to pass a proposal by Del. Gary R. Alexander (D-Prince George's) to increase from $5,000 to $100,000 the criminal fine for thrift officers who knowingly submit false information when applying for a net worth certificate. The certificate is a document that has enabled several savings associations to obtain federal deposit insurance.

The House is expected to pass the full S&L bill this week, but the bill is certain to go to conference committee, legislative leaders said.