The Reagan administration's proposed budget cuts would mean a reduction of about 60,000 federal jobs, and assuming they hit this area proportionately, some 7,000 or 8,000 of them would be lost here, according to administration estimates.

But sources said the administration is not contemplating a governmentwide "reduction in force."

Instead, the job losses would be concentrated in those agencies and specific programs the administration wants to slash or drop.

Many of these cuts would be in the budgets of the regulatory agencies, including the Federal Trade Commission, Environmental Protection Agency and the Consumer Products Safety Commission. Also, officials of the Treasury Department's Bureau of Alcohol, Tobacco and Firearms -- which licenses gun dealers -- said yesterday their agency is being considered for dissolution [Details on Page A7]. To some extent the administration is using budget cuts to achieve regulatory ends.

President Reagan yesterday held a series of meetings with Cabinet members and other officials on the tax and spending cuts he will propose next Wednesday in an address to a joint session of Congress. He later left for a three-day weekend at Camp David during which he will work on that speech and make final decisions on remaining budget matters.

White House press secretary James S. Brady said Reagan had decided on an effective date for the 10 percent personal and business tax cuts but Brady declined to disclose it. Other sources indicated the first 10 percent cut in personal income taxes likely would take effect July 1 rather than be retroactive to Jan. 1. The business tax cuts probably will be retroactive to the first of the year.

Brady said the president rejected a proposal to lower immediately the maximum tax on investment income from 70 percent to 50 percent. The top rate on "earned" income is already 50 percent. However, the three successive 10 percent cuts in personal tax rates Reagan will ask Congress to enact will have the same effect of lowering the top rate on all income to 50 percent.

Among the deepest of the regulatory agency cuts were those recommended for the FTC. They include an effort to shut down the commission's Bureau of Competition, which shares antitrust enforcement powers with the Justice Department. The commission has until tonight to respond to the cuts, which would reduce its outlays this year from the $73.2 million proposed by former president Carter to $66.7 million. For fiscal 1982, the budget would drop further, to $57.9 million, rather than rise to $76.4 million as in the Carter budget.

These cuts would reduce the number of fulltime FTC employes from the 1,665 authorized in the Carter budget to 1,513 by Sept. 30 and 1,388 by the end of fiscal 1982. By the end of 1986, the number would fall to 999 under the Reagan timetable.

Similarly, a cut of at least 20 percent in the $5.3 billion 1982 budget for EPA was appealed yesterday by that agency. A cut of that magnitude probably would halt the agency's new hazardous waste control program, as well as its effort to clean up dangerous chemical dump sites, an EPA official said, since no staff has yet been hired for either program. EPA's plan to control toxic industrial chemicals, already far behind schedule, would progress even more slowly, the official added.

In addition, the administration has decided to bar any further commitments of EPA funds to finance municipal sewage treatment plants after this fiscal year, cutting outlays by $5.7 billion between now and 1986. Payments would continue on projects already under construction.

At the Consumer Product Safety Commission, an official said the 30 percent cut in its 1982 budget proposed by the administration would have "catastrophic" effects on its work.

But while the budget revision exercise has lent a new urgency to the administration's effort to reduce federal regulatory activities, not all of the proposals can be ratified simply by passing appropriation bills. For instance, elimination of the FTC's Bureau of Competition would require amendment of the Clayton Antitrust Act, FTC sources maintained.

Rep. Benjamin Rosenthal (D-N.Y.), chairman of a consumer affairs subcommittee in the House, said he would hold hearings on the FTC and CPSC cuts within two weeks. Rosenthal called the cuts "an unprecedented assault on our independent regulatory agencies."

Administration officials said the looming reduction in federal jobs would have a very uneven impact across the government. "There always are bound to be exceptions," the officials said. The Defense Department, which is expected to get an additional $9 billion this year and $25 billion more next year than Carter recommended, is unlikely to have any personnel reductions. Other sources said the Veterans Administration may be spared, too.

The precise impact of the budget cuts in a particular agency is impossible to predict, federal personnel experts said. Each agency will have to devise its own response to the cuts in line with reduction-in-force regulations the Office of Personnel Management published in the Federal Register on Jan. 16.

In a general way, employes with less seniority are most apt to be let go, but other considerations, such as veterans' preference, nature of the job and so forth, often mean the last-hired, first-fired approach will not prevail.

The hiring freeze imposed last month by Reagan also complicates the situation since it all but rules out transfers from one agency to another. Whether the freeze will be modified if major job reductions are under way is not known.

There are currently a little more than 2 million civilian federal employes. That number has remained about the same for the last decade or so. Pay and benefits for federal workers make up less than 10 percent of the federal budget.