PRAGUE, Czechoslovakia (AP) _ Vaclav Havel toured his vast presidential home on Saturday and placed flowers at the statue of St. Wenceslas to honor political prisoners who fought for change.

The playwright who spent five years in prison for dissident activities used his first full day as the country's first non-Communist president in 48 years to pay tribute to the casualties of the movement he helped lead.

He also met with President Mario Soares of Portugal, also a former political prisoner and the first head of state to visit the new president.

Havel and Premier Marian Calfa appointed a non-Communist interior minister. Government television said the appointee, Richard Sacher, is a member of the People's Party, which was once allied with the Communist Party but has become increasingly independent in the wake of the country's peaceful revolution.

The new president toured the medieval Hradcany Castle, where the presidential office and residence overlooks the city.

''Havel took stock of the premises with which he is not very well acquainted,'' said Michael Zantovsky, a spokesman for the group Civic Forum, which led the revolution.

Havel met for the first time with some members of the staff, who just a few weeks ago were employed by Gustav Husak, the hard-line Communist president. Husak served 21 years and was ousted Dec. 10 by the pro-democracy revolution.

Havel has said he will serve as Czechoslovakia's ninth president only until April, when the first free elections in four decades are to be held.

Havel was accompanied to the statue of Bohemia's patron saint by Soares, who was jailed for battling a right-wing government.

Soares, recognized by the United Nations for his human rights work, returned to Lisbon after the 1974 revolution overturned Portugal's 48-year-old regime.

''Havel and Soares wanted to remember the last five weeks in Czecholovakia and to express their solidarity with students and others who have been beaten or harassed and who were working for a day such as this,'' said student leader Simon Panek, who attended the brief ceremony under gray winter skies.

Soares arrived in Czechoslovakia on Wednesday on an informal visit to last several days.

Later, Havel held a brief informal meeting with his new reform government at the Vikarka Pub inside the walls of the castle, according to a friend of the president's who asked not to be identified.

Havel was unanimously elected Friday by the Communist-dominated Parliament. By early evening, Prague's beautiful streets were filled with people celebrating their victory over the Communist regime. The party lasted until early Saturday. Thousands danced in the cobbled streets to the strains of Bohemian violins or electric guitars.

Men in feathered Moravian hats toasted Havel's health with mugs of Pilsner beer under a giant Christmas tree in the center of the square.

At a nearby bar, several men identifying themselves as former Husak bodyguards gave away bullets.

''We don't have guns anymore, but we have a few bullets left,'' said one burly man.

Pope John Paul II on Saturday offered congratulations to Czechoslovakia's new leaders.

In a telegram to Czechoslovakia's Roman Catholic primate, Cardinal Frantisek Tomasek, the pope hailed the ''great and significant moments in the life of your noble republic.''

He expressed hope the election of Havel as president and Alexander Dubcek as chairman of the legislature marks ''a decisive step toward peace and prosperity in freedom and in the path of (the country's) ancient Christian traditions.''

Dubcek was the Communist Party chief who was ousted after he instituted liberal reforms that were crushed by a military invasion in 1968.