The Department of Health and Human Services, which has been burned in the past by frequent-flier VIPs who allegedly failed to mix business with pleasure, has put out the word to political appointees: The boss is checking your travel costs and destinations.

In a directive aimed at the approximately 45 top HHS political staffers, chief of staff Thomas R. Burke says he's set up a reporting-tracking system so he would know that travel is "planned economically and comports with . . . regulations and the public's highest expectations . . . . I want to eliminate any sense that travel by HHS executives is for any purpose other than the proper conduct of business." HHS has reason to be concerned about its image with the public, Congress and its career staff.

For instance: The appointment of Jean Elder, currently acting assistant secretary for the Office of Human Development, has been put on hold by Sen. Gordon J. Humphrey (R-N.H.). Humphrey questioned eight trips Elder made during a two-year period to Michigan, where Elder's son's college football team was playing games. Those trips were first reported by The Washington Times.

Two years ago, Marjory E. Mecklenburg quit as director of the department's population affairs office after investigators questioned 14 trips she made, including one to Denver where her son, a member of the Broncos, was playing football.

This year, Betty Lou Dotson, an HHS official, resigned as civil rights director during an investigation of more than 120 trips she had taken to 38 U.S. cities and nine foreign countries at a price tag to taxpayers of nearly $87,000.

An HHS official says the memo grew out of "some problems in the past" and wasn't prompted by new queries. "You could say the memo is . . . more like a warning that this area is radar enforced."Postal Picketing

The National Association of Letter Carriers and the American Postal Workers Union, together representing 400,000 members, will bring in troops July 10 for a show of strength at the Postal Service's L'Enfant Plaza headquarters. The current contract between the unions and the service expires in July.

Unlike other civil servants who take what Congress and the White House give them, the heavily unionized postal workers deal directly with top brass of the government-owned mail-moving corporation.

The service's first wage-fringe proposal has been termed "garbage" by the unions' joint bargaining committee. Postal officials say that 80 cents of every postal dollar goes to pay employe salaries and benefits and that first-class postage will have to be raised -- from 22 to 25 cents -- to cover future costs.

Both unions hope that the lobbying effort will impress Congress and that the informational picket line in front of postal headquarters will produce an offer members can't refuse. Despite the tough talk on both sides, a strike is considered unlikely. Retiree Meetings

The Silver Spring chapter of the National Association of Retired Federal Employees will have an installation luncheon 1 p.m. tomorrow at the Langley Park Marriott Hot Shoppes Restaurant. For information call Gerald Gillman on 681-7269.

D.C. Council member John A. Wilson is scheduled to speak during NARFE's Southeast D.C. chapter meeting at 12:30 p.m. Saturday in the Francis A. Gregory Library, 3660 Alabama Ave. SE.

NARFE's Northern Virginia Caucus, representing 4,000 members in 14 local chapters, is having a series of meetings to discuss and develop policy issues.