Argentina last night officially rejected the decision of an international arbitration panel that named Chile the winner in a century old dispute over ownership of three small islands near Cape Horn.

The rejection is the latest development in an increasingly tense situation in which nationalistic tempers are running high and which brought Presidents Augusto Pinochet of Chile and Jorge Rafael Videla of Argentina together last week in an apparently inconclusive summit meeting. Another meeting is planned foro next week, according to Washington Post correspondent Karen De Young.

Similar meetings on ownership of the islands led to a 1971 Argentina decision to submit the issue to international arbitration, the ultimate remedy prescribed in treaties between the two. The International Court of Justice took seven years in study and hearings to make its decision last year.

Argentina at first appeared willing to accept Chilean ownership but balked following the publication of Chilean maps extending that country's territorial waters beyond the islands and into what Argentina considers the Argentine Atlantic.

Perhaps most important are the countriesd' overlapping claims on segments of Antarctica, and the belief that large reserves of petroleum lie under the seabed between the three islands and the Antarctic continent.

Although a Chilean Foreign Ministry spokesman said his government would not comment on the rejection until today, Chilean officials have previously referred to the arbitration as binding and not subject to rejection.