Exactly how does Melina Mercouri propose to get the the Elgin Marbles out of the British Museum and back to Athens?

"We'll make a song," she says, and she raises her arms into the air--the arms of a minister of culture in the Greek socialist government of Andreas Papandreou--as if preparing to launch herself into a "Never on Sunday"-style dance routine.

"Take them back! Take them back!" the actress-turned-politician sings to no melody in particular. Then she laughs--a deep, rollicking, Mercourial laugh--and turns serious.

"Do you think we'll get them back?" she asks, staring intently, her green-brown eyes bright, wide and challenging.

After a period of uncertainty, her questioner replies that it will certainly be "difficult."

"Difficult," says Mercouri, fondling the word. "You know, dictatorship is very difficult, too, and now"--she pauses weightily--"now there is no more dictatorship!"

Mercouri has been a member of the Greek Cabinet since the socialists won power in October 1981. She was here yesterday to publicize her effort to inspire a Greek artistic renaissance through subsidies from her government. Her husband, American movie director Jules Dassin, remained at home in Athens.

"I'm a little tired," she says as she settles into her chair at the Greek Embassy here, straightens the folds of a stylish knee-length brown outfit, and lights the first of several cigarettes.

"You don't look it," says press attache' Louis Danos, sitting opposite her. "You are very young."

Not responding one way or another to the compliment (but, indeed, looking very young at 56) Mercouri presses on with her mission--discussing her program of channeling movie-tax revenues into film production, building provincial libraries and arts centers, spurring archaeological preservation and the like.

"It's a very difficult job, because you have not the budget to maintain all of the treasures that you have," she says, fingering a traditional Greek ring of silver-gray beads as if she were doing complex arithmetic on an abacus.

And the notorious Athenian smog, she concedes, has posed a major additional obstacle to historical preservation. "There was such a destruction under the colonels. For many years Athens became not a very beautiful city."

But the Greek government, according to Mercouri, is beginning to address the problems of pollution and what she calls "the quality of life," pronouncing the word "quality" with an extra, Greek-sounding syllable at the start--"kou-wality."

"I have lost my English!" she suddenly declares, leaning forward in simulated panic. "I know English very well when I was in my exile."

As an actress--a career temporarily suspended, she says, so long as she remains in the Papandreou cabinet--Mercouri takes particular interest in the state of the Greek movie industry.

"We're doing now a new law that will help Greek cinema, because until now Greek cinema is very poor," she says, meaning poor financially. "Eighty percent of the cinemas are playing American films."

Not that she wants to purge American culture from Greece entirely. Mercouri regards the ritual complaints of socialist governments against American cultural "imperialism" as "such a cliche'." In any case, she says, "You can't fight the blue jean. You can't fight the American film or the music. But what we don't want is to have, let's say, dollars as the king of the cultural life of Greece."

For all her other, perhaps more immediate, concerns as minister of culture, it doesn't seem to bother her that her pursuit of the Elgin Marbles has received a disproportionate share of attention. It began, she says, when she casually mentioned the idea during an interview with the BBC, and "poof, it was all over the world!"

She is careful to say she doesn't expect the return of every Greek statue that has ever found its way onto foreign soil. "We are not naive. We understand that the museums cannot be emptied."

But the marbles are different, Mercouri says, because they are part of a "unique monument," the Parthenon. Their return would be no more extraordinary, she argues, than Germany's return of French art treasures at the end of World War II. She says it was a case of unlawful occupation in both instances.

"It was not the will of the Greek people," Mercouri says of the original 1810 transaction, in which the friezes were removed from the Parthenon by Lord Elgin, British ambassador to the Ottoman Empire, which then ruled Greece--and sold to the British Museum for 36,000.

If Greece should ever recover the marbles, Mercouri says, they would become part of "the best, the most beautiful museum in the world," which her government is building on the site of the Acropolis.

Informal British polls of departing museum-goers have encouraged Mercouri to believe that even in England there is support for her position--although another, perhaps more official British view was articulated by Lord Avon, the son of former prime minister Anthony Eden, who said the Elgin Marbles probably would not exist today if they had been left to the mercies of Greek pollution and erratic care.

Mercouri has not visited the British Museum during her ministry, but "when I did 'Phaedra,' " she says, "there was in the prologue of the film the Elgin Marbles."

Quite unexpectedly, and quite vigorously, she slaps herself on the thigh.

"No!" she shouts. "I don't want to say 'Elgin.' The 'Parthenon Marbles,' I mean."

She will be seeing them in person, and generally bearding the lion in its den, during a trip to England next month--an intention announced with a sly wink suggestive of all sorts of unpredictable consequences.

Mercouri appreciates the mythic quality of the battle. She attended a wedding ceremony recently--"a popular marriage, not a wealthy marriage," she says--where a guest was overheard to say: "You see this blond? She was an actress. She was in exile. She married an American, and now she fights with alongside her husband to take back the Parthenon Marbles."

But her entry into politics was not a total break from her previous life. Like Tallulah Bankhead, Mercouri came from a well-known political family. Her grandfather was a popular mayor of Athens and her father served in several cabinet posts.

"I think that I was a political animal from when I was a very young girl," she says. "And I drank the political milk from my mother."

As she rises, she turns on her interviewer and asks, in a demanding voice: "Why have you not a minister of culture in your country?"

To which, she replies conclusively: "You must!"