Gen. Cesar Barrientos, minister of the treasury since Gen. Alfredo Stroessner siezed power in a 1954 coup, died Friday, the government announced. He was 82. The cause of death was not reported but Barrientos had not appeared in public since late last year and had received medical treatment in recent months in Argentina. Barrientos was an army administrative officer when Stroessner came to power and appointed him to the treasury post. Stroessner, 75, recently was elected to an 8th consecutive term in balloting that his critics claim was rigged.