The embassy's offices and the ambassador's residence both lie outside the heavily protected Green Zone in the Iraqi capital, making travel between them dangerous, Amado said.
Embassy staff were "at constant risk of being killed," he said. The Portuguese ambassador to Iraq is already back in Lisbon, reports AP.
Portugal plans to re-open its embassy when security can be assured, Amado said.
Portuguese police participated in peacekeeping patrols in Iraq for two years until 2005. The previous conservative government had supported the U.S.-led invasion, but the center-left Socialist government, elected in 2005, had opposed it.