Employes at the Department of Housing and Urban Development are waiting nervously for the ax to fall as the agency gears up for a major field reorganization that will eliminate 304 jobs.

But while HUD officials say that the reshuffling will save $30.8 million over the next two years, the General Accounting Office says that estimate is overstated.

In the coming weeks, HUD plans to combine nine of its 10 regional offices with area offices located in the same cities. Along with a consolidation of single-family and multi-family housing operations, a HUD official said, the closings "will eliminate duplication, overhead and simplify work flow and reporting relationships."

But the GAO says that HUD's cost estimates are "based on questionable assumptions, which may overstate the true savings to the government." The GAO said that the department overestimated the number of jobs that would be cut from HUD's 9,300-member work force and understated the cost of increasing travel budgets, breaking leases and relocating employes. Moving workers in Dallas alone could cost $400,000.

HUD also failed to consider the workload that could be added by possible new programs, such as a congressional proposal to help unemployed homeowners avoid foreclosure, the GAO said.

"This is where the guts of HUD is in terms of service delivery to constituents," said an official with the American Federation of Government Employes. "They are further dismantling the agency." The AFGE official added that when HUD's headquarters had a reduction-in-force last year "the people who hit the streets overwhelmingly were union members or whistle blowers or had filed grievances."

A HUD official, however, said that he expects most of the jobs to be eliminated through attrition rather than layoffs. CLOSING UP SHOP . . . One of the few employes not trying to hang on to his job is Warren Lindquist, director of the agency's New Communities Development Corp. Lindquist is in the process of liquidating the corporation and transferring its employes to other divisions.

The program was conceived in the late 1960s to develop "planned communities" as an alternative to suburban sprawl. The result: Nine of 13 new towns had to be acquired by HUD in foreclosure, and the agency has sold the assets of every town except one and absorbed total costs of $570 million.

"I would not consider the program a success," said Lindquist, who was hired to clean up the mess. "I'll have worked myself out of a job, but this was not a career for me." HOTLINE HARASSMENT . . . Agency employes will be getting an unexpected message from Secretary Samuel R. Pierce Jr. in next month's in-house newsletter.

Pierce's statement is part of a settlement in a grievance filed by William C. Tuesburg, an employe in HUD's St. Louis-area office. Tuesburg charged that after he phoned in a complaint to the HUD inspector general's "hotline," a superior criticized him and lowered his performance rating.

In an agreement with the Merit Systems Protection Board, HUD agreed to upgrade Tuesburg's rating, and Pierce agreed to publicize the incident. "I want to reemphasize that communications between HUD employes shall remain unfettered," Pierce wrote.