The government's 17 inspectors general are about to unleash a new version of the weapon that has become the darling of the war on waste and fraud.

The President's Council on Integrity and Efficiency yesterday said it plans to equip the IGs with briefcase-sized microcomputers that it said will be able to tap into government computers and within seconds retrieve information that once took weeks to compile.

Joseph R. Wright Jr., deputy director of the Office of Management and Budget and head of the council, also announced that the Reagan administration will have a computerized debt-collection system in place by August that will tell federal agencies whether a person previously has applied for a government loan or whether he is seeking help from more than one agency.

Such "pre-screening" should prevent instances such as the recent case in which a person obtained two loans from the Agriculture Department, one from the Small Business Administration and another from the Army Corps of Engineers--and defaulted on all of them, Wright said.

The IGs also will step up their successful computer matching program that allows investigators to compare different government lists and identify, for example, which federal employes have not paid their federally backed college loans.

Wright discussed the new effort at a news conference marking the release of the IGs' biannual report on the savings they have achieved.

Between Oct. 1, 1982, and March 31, 1983, the IGs completed 39,000 audits that saved the government $5.4 billion, Wright said. That includes $45 million in criminal and civil penalties, $805 million in accounts that "the IGs are committed to collect" and $4.5 billion in savings from "costs avoided because of IG recommendations."

That brings the total amount that the council has claimed the IGs have saved over the past two years to $22.3 billion. Congressional critics have contended that the council's estimates are misleading because the bulk of them ($19.4 billion) fall under the "cost avoided" category.

But Wright said yesterday that the IGs' role has shifted from uncovering abuse to preventing it and, he claimed, prevention would result in much larger savings than detecting schemes that bilk the government.

As part of that shift, Wright said the IGs will become more involved in the drafting of regulations and designing of management systems so that potential loopholes that could lead to fraud are discovered at the start.

The government hasn't purchased any of the portable computers that Wright displayed yesterday. Wright said the IGs currently are figuring out how many of the $6,000 machines will be needed.

The government now has more than 100 different types of computers, Wright said, and most of them can't "talk to each other." But Alan Duncan, a member of the inspector general's staff at the Transportation Department, said the portable computer could be linked with any of the government's existing hardware--although some connections might require additional programming.

Duncan, who demonstrated the computer yesterday, said, for example, that it would be able to sort through hundreds of DOT contracts and in seconds display the ones that had fewer than three bidders and a difference of less than $5 million between the bids--a sign of possible bid-rigging. That information now takes four auditors up to four weeks to obtain, he said.