The premier event in soccer - the quadrennial World Cup - begins here Thursday amid anxieties concerning security and competition.

Weeks ago two bombs were found in the press center, one exploded, killing a police inspector.

As to the soccer itself, no one is happy about playing the Argentinians in Buenos Aires. Lajos Baroti, the 64-year-old coach of Hungary, which opens group one against Argentina in the River Plate stadium Friday, said he fears the referees will be influenced and intimidated to not give Argentina penalties.

"The success of Argentina is financially very important for the tournament," he observed wryly.

The Argentinians say this won't happen, that Cesar Menotti, the agreeable young team coach, is against violent football, that he has, for example, excluded Pernia, a defender notorious for his rougness. (Pernia was sent off the field against Scotland here last June for punching little Willie Johnston in the Kidneys. However, the referee sent off Johnston as well).

Argentina seems to have the forwards and midfielders to field an open, footballing team. But the Buenos Aires crowd is frightening, and if Menotti has excluded Pernia he has retained Daniel Bertoni, sent off for punching Trevor Cherry in the mouth when Argentina met England six days before the Scotland game.

The competition is divided into four qualifying groups, of four teams each, plying in Buenos Aires, in the rainy coastal resort of Mar del Plata and in Cordoba, Mendoza and Rosario.The top two teams in each group (two points are awarded for a win, one for a draw) go into the two final pools of four teams each. The winners here meet in the final June 25.

It is World Cup without an obvious favorite, although Brazil and Holland seem to have the most potential. When the Brazilians came to London's Wembley in April they kicked everything that moved, disgraced themselves and were lucky to get a 1-1 draw. But since returning to Rio they've played better, especially in a 2-0 win in heavy rain at Maracana Stadium against the Czechs.

There is no doubt that Capt. Coutinho of the Brazilian army, the team's coach, was encouraging a policy of blood and iron, which had a deadening effect on the traditional Brazilian game of flair and ball control. Ferocious criticism in the press, both at home and abroad, seems now to have induced him to change.

Brazil lacks at least two good strikers, a left back and a central stopper, but has superb midfield players in Rivelino, Cerezo and Zico. Now that 21-year-old center-forward Reinaldo is back in favor, there is much scoring potential.

Brazil is in the Mar del Plata group and opens against Sweden. That wilkl be a difficult game, because the Swedes appear to have struck from and, in sharp contrast with other European teams, seem to be in excelent physical condition.

The other two European teams in this group are Spain, captained by the splendid 33-year-old attacking sweeper Pirri, who made his debut for Spain in the 1966 World Cup at Birmingham, and Austria. The Austrians recently lost, 1-0, at home to Holland. They are physically strong and combative, have clever play-maker in Prohaska, but seem the weakest in the group. All three European teams are sure Brazil will qualify and that the other place must be contested by the three of them. Spain has few stars, but much grit.

West Germany, the much-diminished World Cup holder, opens the tournament in Buenos Aires on Thursday against the Poland, which the Germans were fortunate to beat in 1974 on a flooded Frankfurt field. The loss of Frank Beckenbauer to the Cosmos has been catastrophic. Berti Vogts, the coach, seems vulnerable now in defense, but the Germans were convinced they will play much better than when they lost in Stockholm, 3-1, against Sweden.

The Poles have many of their 1974 World Cup players back, but this time they won't enjoy the advantage of surprise. The weakness of the other two group members, Tunisia and Mexico, should allow both the Germans and the Poles to qualify.

In the Cordoba group are Scotland, depressed by its failure to win any of the three British championship games: Holland, the grand enigma; Iran and Peru. Dutch journalists are singing the same woeful song heard four years ago when Holland nearly won the World Cup. It is true that the incomparable Johan Cruyff has gone, that preparation has been sketchy, that Ernest Happel, the Austrian who coaches the team, spends most of his time with the Bruges club of Belgium. Yet Holland still has stuch marvelous players as Rob Rensenbrink, that ultra-versatile winger, and Aarie Haan, a midfielder now, sweeper in 1974.

Scotland also abundant talent, especially in midfield with Asa Hartford, and the problem is who to leave out.

Argentina, which is in group one with Hungary, Italy and France, must be taken seriously. That prolific scorer, Mario Kempes, has come back from Spain, Ardiles is a busily effective midfielder, Rene Houseman a delightful little winger and Passarella is a powerful center-half who can also score. The Italians seem tired and out of ofrm, and their three shtrikes, Causio, Bettega and Graziani, will need to improve substantially.

Hungary looked slow and inept, when, it was beaten 4-1, by the English at Wembley, though little center-for.

Ward Toroscik had delighful moments. France relies heavily on its goal-scoring midfielder, Mitchel Platini, though it has a superlatively effective sweeper in Marius Tresor, from Guadeloupe.