MEXICO CITY (AP) _ The Organizing Committee dismissed as ''speculation'' published reports that the group heads for the 1986 World Cup soccer tournament already have been chosen.

''Only two teams can say they have secured positions as heads of group - Italy and Mexico,'' the Committee's press office said in a statement Tuesday.

Italy is the defending champion and has been chosen to lead the group playing in Puebla. Mexico, as the host team, will lead the group playing in Mexico City's Aztec Stadium.

There are four other groups with four teams in each playing in Guadalajara, Monterrey, Queretaro and Leon. But they have not been selected yet, the statement said.

As a rule, defending champions with good fan-following are seeded as heads of group in order to ensure a good box office and to keep the top teams from eliminating each other in the early rounds.

The decision is made after discussions by the 20 members of the Federation of International Football Association's executive committee on Dec. 14, the day before the World Cup draw. The association is popularly known by its initials of FIFA.

Top FIFA officials already have expressed their own personal choices for heads of group.

Guillermo Canedo, president of the organizing committee, has said publicly he would like to see Brazil as head of the group playing in Guadalajara because the Brazilians are very popular there. They played in Guadalajara as heads of the group in the 1970 World Cup when they won the championship.

Canedo said he also would like to see West Germany as the leader of the group playing in Queretaro and Nezahualcoyotl.

European FIFA officials also have expressed their own choices, but they differ from those of some South American officials who would like to see teams like Argentina or Uruguay, both former champions, as heads of group.

Argentina, it is speculated, would like to play in the Leon-Irapuato group or in Monterrey. England, another former champion, also would like to be head of a group.

But the final decision is up to the FIFA committee and will be made on Dec. 14, the committee's press office said.

The inaugural game of the month-long tournament will be played at Aztec Stadium on May 29.