Federal employe groups yesterday attacked reported Reagan administration proposals to freeze federal workers' pay and change their retirement system, branding them a "hog wild" and "crazy, shotgun" approach to management of the bureaucracy that would cripple employe morale and recruitment.

Using some of the strongest language in their battle with the administration, federal employe union representatives said they would use every available lobbying and public relations tactic to block the White House budget proposals in Congress.

"If the telephone calls are any indication, it's scaring the hell out of our people and making them very mad," said Kenneth Blaylock, president of the American Federation of Government Employes, the nation's largest federal worker union. "They now know they have an employer who could care less about them."

Blaylock, saying Reagan's "crazy, shotgun proposals have no rationale," said he and other union leaders have sent a telegram to the president, requesting a meeting.

Reagan's reported proposals to freeze federal civilian and military pay this year, lengthen the retirement age for full benefits from 55 to 65 and force government workers to contribute more of their salary to their retirement fund seems to be the proverbial "last straw," most employe groups indicated yesterday.

"There's not a single benefit they haven't attacked--there's nothing left," said George Gould, legislative assistant for the National Association of Letter Carriers.

Reagan's budget also would change the formula used in calculating pension benefits to reduce future annuities. The administration has reduced federal employe health benefits and wants Congress to put new government workers under Social Security.

The Office of Personnel Management would not comment on reports about a pay freeze and retirement benefits reduction. But OPM Director Donald J. Devine issued a statement in effect confirming that some changes could be expected. However, he said retirement system alterations would be gradual. "We will not propose any changes in benefit computations affecting any current employe who is already age 55 or older with 30 years of service," Devine said. He said any proposed changes in retirement benefits for employes under 55, with 30 years of service, would " . . . be phased in and would allow credit for the years served. . . ."

Several union and employe spokesmen complained that by releasing a barrage of proposals affecting federal workers, the administration hopes to diffuse the opposition.

"It's a great strategy," said Steve Skardon, legislative representative for the National Association of Retired Federal Employes. "These proposals are not researched, they're just whipped up by the political people at OPM and thrown at us."

Skardon said federal pay lags behind that of the private sector by 20 percent. A majority of private firms allow retirement at age 55, and 80 percent of them completely fund the retirement system for their employes, he added.

"Reagan is trying to make federal employes the scapegoat for the total failure of his economic policies," said Robert Tobias, executive vice president of the National Treasury Employes Union. "We're not going to have to work very hard to get our people excited about this."

Gould and other union representatives said they would be holding news conferences soon, taking out newspaper advertisements and sending their rank and file out to pressure members of Congress here and at home to fight the proposals.

Sandra Arnold, a spokesman for the National Federation of Federal Employes, said Reagan's plan, especially the pay freeze, "squeezes the federal and military work force to cut the budget. It seems the human factor is the only one he's willing to compromise on--he won't give up any of his weapons."

She said she found the White House proposals particularly distressing "since this was supposed to be public employes appreciation week." Congress and the president had declared next Monday as Public Employes Appreciation Day in honor of the century-old modern civil service system.