A federal judge in New York, after hearing arguments for a hour and a half on whether the U.S. government should be allowed to deny visas to 315 foreign peace activists seeking to attend a U.N. session on disarmament, delayed a decision until today because the U.S. attorney had not fully presented his case.

U.S. Attorney Thomas Belote, defending the government in a case brought by the New York Civil Liberties Union, told the court that he had spent most of yesterday in Washington taking statements from government officials explaining the decision to deny the visas.

The statements will be ready to be presented today, said U.S. Attorney Peter Salerno, and may contain "sensitive foreign policy" information.

U.S. District Judge Pierre Leval said he would not rule on the request for a temporary restraining order against the visa denials until he reads the statements.

Most of the foreigners whose visas were blocked are members of the Japanese antinuclear group Gensuikyo, an organization with ties to the World Peace Council.

The State Department says both groups are "proscribed organizations" under the 1952 McCarran-Walter Act, which bars entrance to this country of aliens affiliated with communist or anarchist groups unless special circumstances warrant otherwise.