Buoyed by political support in the White House and procedural change in Congress, defenders of the Renegotiation Board expressed optimism yesterday that Congress will pass long-standing proposals to strengthen the board, which is the government's excess profits police force.

At the start of three days of hearings on legislation to tighten the board's powers to recapture excess profits earned on government contracts, House Banking Subcommittee chairman Joseph Minish (D-N.J.), asserted, "We'll get this bill through both houses this year."

Last year Minish pushed e package of renegotiation changes through the House, but the bill died in the Senate when Finance Committe Chairman Russell Long (D-La.), declined to act on it.

In the 95th Congress, however, Senate jurisdictions over such bills has shifted to the Banking Commitee, chaired by Sen. William Proxmire (D-Wis.), an outspoken advocate of tougher renegotiation.

"We probably had the votes for it last year, so I'm hopeful the bill will pass this time," Proxmire said yesterday.

Both Minish and Proxmire were noticeably cheered by President Carter's apparent support of a stiff position on renegotiation. Last month, Carter fired two of the board's five members who had been criticized for dealing too tenderly with large government contractors. The President promoted Goodwin Chase, whom Minish has called "the only real tiger on that board," to the chiarmanship.

The 25-year-old board reviews the Defense State and General Services Administration contracts to see how much profit the contractor has realized after the work is completed.

If the board concludes that a given contractor has made "excessive" profits in its dealings with the government as a whole it can order the excess amount refunded.

In fiscal year 1976 the bill recovered $40 million in profits on about $41 billion or renogtiable business. The board supporters say the amount recaptured would take a quantum leap if the board's staff of 200 were significantly increased.

But opponents of renogotiation - mainly the businessmen who are subject to it - see it as an enormous engine of harassment and red tape that discourages business from deailing with government.

Rep. Paul N. McClockey Jr. (R-Calif.) whose northern California district is the home of unmerous electronics firms that deal with the government, said the total cost to business in paperwork and personnel needed to handle renegotiation matters probably exceeds $350 million annually.

McCloskey and Rep. Paul Trible (R-Va.) agreed that business is "over-regulated" by the government and should be spared from renegotiation.

Minish, chairman of the House Banking Committee's oversight sub-committee, dealt caustically with witnesses who oppose his renogiation proposals.

He berated Tirble when the Virginia freshman failed to note that his district is the home of Newport News Shipbuilding and Drydock Co., a major defense contractor.