As the Vatican is straining to complete preparations for the new pope's latest foreign trip, there are growing indications of an uncharacteristic turmoil within its ancient vaulted rooms.

Outwardly, the tourist view of the Vatican has remained the same with the daily busloads of visitors and throngs in St. Peter's Square.

But the hidden Vatican -- once a quiet orderly place where cassocked monsigniori drew on centuries of experience to govern the affairs of more than 700 million Roman Catholics -- is confronting new problems. The unhurried pace of the past seems increasingly inadequate to the demands of the present.

By the first anniversary of his election as pope last October, John Paul II will have visited five countries in the course of three major trips, with more to come after his Irish and American travels beginning this weekend. He also regularly makes excursions outside the Vatican walls here at home.

The activities of the Polish-born pope and the widespread interest they gnerate have made him a focus of journalistic interest unprecedented in Vatican history. His enormous personal popularity and relaxed style have produced extraordinary security problems.

The Vatican simply has not had to cope with anything ot this magnitude before. What clearly is becoming a "papacy on wheels" suggests a need to reshape Vatican relations with the outside world and specifically press relations.

All of this has to be done by a bureacracy dominated by Italians on behalf of the first non-Italian pope in more than four centures, the pontiff whose style and approach differ markedly from that of his predecessors.

Over the years, the traditionally secretive and close-mouthed officialdom here kept Vatican reporters at a distance. These in turn have grown to rely heavily in their reporting on the moods, trends and interpretations of the more accessible and outspoken Jesuits.

But the demand for harder concrete information is growing. It is placing increasing pressure on the tiny, understaffed press office that has been working at its usual slow, steady pace keeping its in-depth contacts with reporters to a minimum. This, of course, further infuriates many newsmen.

The head of the office is the Rev. Romeo Anciroli, a small, spare man with steel-rimmed glases whose white hair contrasts sharply with his black clerical garb. He is said to understand English even if he does not show it and appears to speak only Italian.

He is calm and betrays no outward signs of rush or worry, but in recent weeks he has been taking few calls and receiving few visitors while his spartanly equipped pressroom grapples with an avalanche of requests -- for advance notice of the papal itinerary in Ireland and the United States, for ticket payments to the Irish airline, Aer Lingus, and the American TWA, for obtaining specially produced Vatican press cards that the Vatican is struggling to get printed in the approved shade of yellow and for texts of the pope's speeches during his hectic journey.

Handling the press is only one of the problems confronting the Vatican in preparing for this trip. John Paul's papacy, with its unusual activity and impromput moves, has placed strains on the entire Vatican structure.

Insiders report turmoil in some of the inner Vatican offices. Members of the English-language section have been working around the clock in an effort to finish the approximately 50 speeches the Pope will make, and then translate, copy and ship them ahead of his schedule arrivals.

Critical decision-making has been taking place in other offices.

Some of the decisions have been difficult, such as whether to go to pnorthern Ireland and the entire question of security. Some have been delicate politically, such as whether to accept other U.S. invitations and, most significantly, which cities and areas not to visit on this trip.

Others are logistical but no less time consuming: arranging for traditional shifts for the American and Irish Cardinals, and for the many participants in the offertory processions that will accompany each papal mass, and choosing not only the 18-man papal entourage that goes with John Paul on his plane but the 70 journalists -- a fraction of the total request -- who will accompany the papal party.

Given the Vatican tradition of secrecy, no one knows just who has been involved in these and other decisions. But it's generally assumed that a prime mover behind-the-scenes has been a bulky American bishop from Chicago, Paul Marcinkus, a former athlete who has been dubbed "the pope's bodyguard" because of his ability in crowd control.

Although in private Marcinkus can be an amusing conversationalist, his refusal to make statements or give interviews has lent him something of the air of a mysterym man.

The Italian press, alway eager for the scent of scandal, has taken his position as also the Vatican's banker and linked him conspiratorially several times with a Sicilian financier, Michele Sindona -- a situation that has hardly improved Marcinkus' rleations with the press and his willingness to deal with it.

In fact, Marinkus is like an American political "advance man," the person who prepares the way for the candidates caravan, attending to the laborious but essential details of motorcade, hall and logistics.

He has been doing this since the trips of Pope Paul VI, whose journeys to the United States, Jerusalem, Southeast Asi and Latin America broke with a historic stay-at-home papal precedent.

But Paul, for all his shattering of Vatican walls, was a figure from the steam age when compared to his ebulient and energetic Polish successor.

Already John Paul's desire to be open and informal and to be seen around the world as often as possible, has shaken the sedate and reclusive Vatican as nothing before. His eagerness to break with tradition became apparent on his first encounter with the press. A picture taken then shows the pope warmly clasping the hand of a woman journalist while an aide looks on in horror.

Since then he has continued to trample on tradition. On his trip to Mexico in January, he spoke at length with several journalists, all the while being photographed by television cameras. Recently, during a general audience, the pope surprised an American TV crew -- and again startled his aides -- by coming forward with an unsolicited message for the American people.

To Vatican traditionalists, all this is surely bewildering if not upsetting. But the lesson of this pope already seems clear: They are going to have to learn to live with, and adapt to, a very different kind of papal era and world papal presence.