The 150,000 federal workers who were to begin furloughs next week can relax but only for a couple of weeks,

Next round of nail-biting will be even worse.

The surprise Senate and House votes to override President Reagan's veto of the $14 billion supplemental appropriation bill means that agencies will have enough money to meet payrolls for the rest of September.

But an even more serious paycheck problem looms for October.

That is because Congress has still not approved a single agency budget for the fiscal year that begins Oct. 1. A few may be cleared, or partially cleared, within the next couple of weeks.

But many agencies could well enter the federal new year technically broke.

Congress can solve the problem by approving a continuing resolution--emergency stopgap spending authority--that will permit agencies to keep meeting their obligations (among them paying employes' salaries) at the current (fiscal year 1982) level.

But until that happens, most, if not all, federal agencies will be out of money starting in October.

Even if they get budgets--or temporary spending authority--many agencies still face money problems that could force them to furlough or fire people.

Part of the problem stems from the 4 percent raise that most white collar workers are due to get Oct. 1.

If, as expected, Congress makes agencies absorb most of the cost of the pay raise, some labor-intensive agencies (where most of the money is spent on employes rather than programs) will probably have to run RIFs.

Because of the high first-year costs of a RIF (agencies must pay severance, lump sum benefits due fired workers and their unemployment benefits) most agencies prefer to run RIFs at the beginning of the fiscal year.

The longer they wait to RIF, the more people must be let go to accomplish the same dollar savings.

In addition, Congress may force federal agencies to pay all or part of the employer share of the new Medicare tax that will be slapped on U.S. workers in January.

Beginning next year, government employes will have to pay 1.3 percent of their salary (on amounts up to $35,000) into the Medicare fund. Since employers must match that contribution, agencies may have to come up with their 1.3 percent matching payment to Medicare too.

Agencies that are at or above their manpower ceilings may be forced to furlough or fire because of the added pay and Medicare costs.

Also, if Congress and the White House play games with the continuing resolution(s) (and we all know that can, and does, happen) massive furloughs could be required.

Breach of Contract: Don't hold your breach waiting for government unions to sue Uncle Sam over recent cuts in federal retirement benefits.

A number of organizations have explored the feasibility of suing the government over recent congressional actions to cap, or delay pensions and have concluded they wouldn't stand much chance of winning.

Beginning next year, federal retireees who are under 62 will get only a portion of the cost of living raise that other federal retirees will receive.

Best guess is that 170,000 federal retirees, and more than 800,000 military retirees, will be penalized because they are under age 62.

In addition, Congress has voted to defer the next COL raise (normally payable in April) until May of 1983, the 1984 COL until June, and the COL adjustment for 1985 until July of that year.

Many federal and military people (particularly those forced to retire before age 62) feel the government is guilty of a breach of contract by changing the rules now.

Others claim that Congress is guilty of age discrimination against the under-62 crowd. Maybe so.

But the Supreme Court, on several occasions, has held that the government can change its benefits if it demonstrates it had a good reason -- like saving money.

That is exactly the argument Congress used when it did what it did.