Treasury secretary-designate Lawrence H. Summers promised to carry on the policies set by outgoing Treasury Secretary Robert E. Rubin at an easygoing Senate confirmation hearing yesterday that won Summers words of praise from both sides of the aisle.

Senate Finance Committee Chairman William V. Roth Jr. (R-Del.) predicted overwhelming approval when the panel votes next Tuesday after a delay to allow Summers to answer some questions in writing. Sen. Daniel Patrick Moynihan (D-N.Y.) said he thought the vote would be "close to unanimous." Roth said he hoped the full Senate would vote on the nomination before July 4, when Rubin plans to leave office.

Summers, who is now Rubin's deputy, has been a senior Treasury official since the early days of the Clinton administration, and his familiarity with the committee was obvious during the three-hour session yesterday. Roth referred to the nominee repeatedly as "Larry" and said he could "go on and on" about Summers's credentials, which include having been the youngest person ever to be named a tenured professor at Harvard University, a feat Summers achieved at the age of 28.

For his part, Summers, 44, followed all the unwritten rules for being a good confirmation witness. His family sat behind him, provoking several senators to fawn over his twin 9-year-old daughters and his 5-year-old son, who sported a red tie for the occasion.

Summers has sheathed a rapier-like disdain that early in the administration's tenure used to ruffle congressional feathers. He was deferential and responsive to his interrogators and deeply respectful of the soon-to-depart Rubin. "At Treasury, on the economic issues and the others we face, the right course has been set," Summers said. "Our challenge will be to carry on."

Summers pledged to seek to maintain budget surpluses, a strong dollar and respect for an independent Federal Reserve Board. Although Social Security and Medicare reform plans appear all but dead until after next year's elections, he said he would make it a top priority to try to overhaul both programs.

In response to mostly gentle questioning from the panel, he restated the White House's view that there should be no big tax cut along the lines Republicans want until Congress and the White House agree on how to use budget surpluses to shore up Social Security and Medicare.

Interestingly, the only uncomfortable exchange came with Democrats, when Sen. Bob Kerrey (D-Neb.) grilled Summers on the administration's proposal to overhaul Social Security by transferring future budget surpluses to the program's trust fund. Kerrey has a competing Social Security plan that would take a different tack.

Kerrey questioned Summers repeatedly over how those trust fund IOUs would be turned into actual cash to pay beneficiaries. When Summers was slow to respond, Moynihan broke in with exasperation: "Larry, it's taxes," explaining that the money would come from individual and business taxes.

Kerrey said the White House plan would worsen Social Security's problems, but Summers defended the administration proposal. "We would see it differently," he said.

On the prickly issue of steel imports, Sen. John D. "Jay" Rockefeller IV (D-W.Va.) criticized the administration's refusal to back a bill that would place quotas on low-priced imported steel, insisting the United States had become "a dumping ground" for foreign steel. Summers reiterated the administration view that putting quotas on steel imports would invite foreign retaliation against U.S. products.

In other matters, Summers apologized again -- twice -- for a 1997 comment that enraged Republicans, when he said that "selfishness" motivated those who wanted to repeal the estate tax, a top GOP priority. "What I said was wrong," Summers told Sen. Connie Mack (R-Fla.), noting that he had quickly retracted the comment the day after he made it.

He also defended his high-profile role in helping to orchestrate financial rescue missions by the International Monetary Fund in Asia, Russia and elsewhere. While he acknowledged there was "room for improvement" in the way the IMF handled the crises, he defended the broad thrust of the policy. He asserted that countries that complied with IMF policies have fared better than those that did not, such as Russia and Indonesia.

CAPTION: Lawrence H. Summers testifies yesterday at his confirmation hearing, where he was praised by members of the Senate Finance Committee.