UPDATE 1-Iran denies U.S.-born reporter on hunger strike

* U.S. State Dept voices concern over Saberi's health

* Official urges release, cites lack of transparency

* Iran judge says hunger strike raised as propaganda issue

* Case could derail U.S. effort at reconciliation (Adds State Department official's comments, paragraphs 4-6)

By Fredrik Dahl

TEHRAN, April 28 (Reuters) - Iran's judiciary said on Tuesday a U.S.-born journalist jailed for espionage was in good health and not on a hunger strike, but Roxana Saberi's father said she was "frail and weak" after refusing food for a week.

Reza Saberi said his daughter, who was sentenced on April 18 to eight years in prison on charges of spying for the United States, had not eaten since last Tuesday.

He told Reuters he had failed to persuade her to stop the protest action while visiting her in Tehran's Evin prison.

U.S. State Department spokesman Robert Wood also voiced concern about Saberi's health and urged Iran to free her.