Health-industry lobbyists unable to gain the briefest audience with Joseph Califano, the secretary of health, education and welfare, can spend a whole evening with him here June 27 - by shelling out a mere $500.

That money would enrich the campaign war chest of Rep. Andrew Maguire, a liberal Democrat from New Jersey whose views collide with the lobbyists' clients. For that $500, the lobbyists not only get "an intimate dinner" with Califano but also cocktails with the secretary of transportation, the speaker of the House and assorted congressional grandees playing key roles in health legislation.

The annual lobbyist shakedown is clearly alive and well in Washington, almost undiminished by post-Watergate morality. Pressure for campaign contributions from lobbyists is traditionally applied by Republicans and Democrats alike, though most heavily by the party in power it can always order up Cabinet members. Jimmy Carter's non-imperial presidency and the advent of reform congressmen such as Maguire have changed nothing.

What is billed as "an evening with two members of the president's Cabinet" to help Maguire's "campaign fund" is in the grand tradition. The evening begins at 5:30 p.m. with "cocktails" at the Folger Shakespeare Library. Rep. Paul Rogers of Florida, chairman of the House subcommittee considering health-cost containment (which includes Maguire), will be present. So will two other senior members of the parent Commerce Committee. Reps. John Moss (D-Calif.) and John Dingell (D-Mich.).

For lobbyists outside the health field, the pickings are joyful: Transportation Secretary Brock Adams; Sen. Harrison Williams of New Jersey, chairman of the Senate Labor Committee; Rep. Thomas Ashley of Ohio, chairman of the House Special Energy Committee, and even Speaker Thomas P. O'Neill.

That costs $100. For another $400, says the invitation, "an intimate dinner with Secretary Califano will follow the reception" at a private home nearby. Since lobbyists seldom penetrate the HEW secretary's inner sanctum, this provides a golden opportunity for a lobbyist to pay his fee and make his case.

Califano is becoming legend for cavalier treatment of businessmen. He recently kept one health-insurance executive waiting 60 minutes beyond the appointed hour, then announced he was too busy to see him. But the secretary has no idea who his dinner partners will be June 27. "The guest list is the congressman's responsibility," a Califano aide solemnly told us.

If Califano does not know who is invited, Maguire is not telling. "Are you serious?" cracked the congressman when we requested the names solicited. Maguire is the beau ideal of the famous Watergate class of 1974 elected after Richard Nixon's disgrace, advocating open government and candor. But when we questioned him, he displayed some of the testiness and secrecy of the bad old days. Did he solicit a list of lobbyists? "We have simply mailed to people I know or to people known by people I know or to lists provided by them," he answered. But does that include list of lobbyists? "I've answered your question," he snapped.

Actually, Maguire probably could not supply the list. One health-industry lobbyist who has never met Maguire was invited by a mutual friend to a recent planning session for the $500 affair, attended by business lobbyists, at a Washington law firm's conference room. Each agreed, in chain-letter style, to produce 20 new prospects. The health lobbyist soon received from Maguire 20 blank invitations, which he mailed to his own list to 20 lobbyists.

Every health-insurance lobbyist we checked had received an invitation, though few had ever met Maguire. "I wouldn't know him if he walked through my door," said one who has been prodded by telephone on three occasions since receiving his invitation.

There are signs, however, that the old lobbyist shakedown may not be quite as alive and well as it used to be. One health-insurance lobbyists, with a good record of Democratic Party activism, has been unable to gain an audience with Califano. "I'll be damned if I'll be blackmailed or allow clients to be extorted to sit down and have dinner with Joe Califano," he told us. Another lobbyist, also a faithful Democrat, said: "It's shameful, it's outrageous and it's been going on forever."

Our spot check showed no acceptances yet by health-insurance lobbyists, a large part of the health lobby. Only one - representing Nationwide Insurance - indicated a clear desire to go if he could get home-office clearance.

Apologists say such shabby methods are necessary for electing outstanding congressmen against tough opposition. But Rep. Barber Conable of New York, senior Republican on the House Ways and Means Committee, never has solicited Washington lobbyists, nor accepted more than $50 from anybody, even when facing a strong challenge from Democrat Midge Costanza in 1974. So maybe there is a decent alternative to the old-fashioned shakedown.