The flurry of "campaign" fund raising and spending reported by Mayor Marion Barry's campaign committee last week, totaling more than $28,000 since the general election, almost makes one forget for a minute that the mayor's race ended six months ago.

No legal questions have been raised about Barry's post-campaign spending, which included catered meals, air travel, the purchase of balloons and "medical services."

Traditionally, the press and watchdog agencies have paid considerable attention to the sources of campaign contributions but little to how those funds are spent. Incumbent officeholders have been able to exploit loopholes in the election laws and lax enforcement policies to spend campaign funds on activities not related to their campaigns.

But a Washington attorney who specializes in federal election laws noted last week there is a growing awareness of the potential for abuses of campaign expenditures, at both the local and federal level.

An article entitled "The Senate's Secret Slush Funds" in the current issue of The New Republic concluded more than a dozen senators channeled campaign contributions into their own checking accounts in 1981 and part of 1982 to pay expenses they are either unable or embarrassed to submit for official reimbursements. Those expenditures covered everything from softball shirts for their Senate staffs to airline travel for their children.

Authors Bill Hogan, Diane Kiesel and Alan Green cited dozens of cases in which they said Senate incumbents have ignored Internal Revenue Service regulations, violated federal election law and evaded standards for public disclosure and accountability. The authors made similar findings in an investigation of campaign spending by House members that was published last year.

Until recently, the potential for similar abuses in D.C. politics seemed remote, primarily because of the relatively small size of campaign budgets. But the District entered a new era of big-time politics last year when Barry and his top Democratic challengers raised millions of dollars in contributions. Barry alone raised $1.33 million during the primary and general election campaigns.

The final accounting of receipts and expenditures that Barry's campaign committee filed last week before finally going out of business appears to be "substantially in compliance" with D.C. election law, according to Keith Vance, director of the D.C. Office of Campaign Finance.

The District's relatively weak campaign finance laws place little pressure on candidates to disclose in detail how they spend the money they raise. What's more, the law gives candidates wide latitude in spending campaign funds, so long as those expenditures are reported. Incumbents who win reelection even may transfer surplus campaign funds to their office accounts and virtually spend the money as they see fit.

In short, the line dividing expenditures for purely campaign-related activities and nonrelated events is at best a blurred one.

Last fall, it looked as if Theodis R. (Ted) Gay's job as head of the local Democratic party might be in jeopardy. Mayor Barry was miffed that Gay had discouraged the D.C. Democratic State Committee from taking sides in Barry's tough primary battle with Patricia Roberts Harris. The mayor privately threatened after the election to take control of the party and dump Gay.

But last Thursday night, Gay was unopposed as he won election to a second two-year term.

Gay is a likeable but rather dull political leader who prefers tending to the nuts and bolts of fund raising and organization to getting out front on hot issues. While a handful of Barry partisans and dissidents from Wards 7 and 8 grumbled about his stewardship, most state committee members believed Gay deserved a second term--if for no other reason than he retired the party's $35,000 debt.

And speaking of unopposed candidates . . .

Ron Richardson, secretary-treasurer of Local 25 of the Hotel and Restaurant Employees Union and probably the most controversial labor figure in Washington, was reelected without opposition last week.

Richardson was part of a slate of officers elected to three-year terms, including President Minor Christian, First Vice President Joseph Beavers, Second Vice President Lou Bruns, Third Vice President Phinis Jones and Recording Secretary John Boardman.