Iranian football followers have questioned "cab-drivers, immigration officers and hotel maids" about the fitness of the Irish team's captain, Roy Keane, according to a visiting fan, Mr Mike Alborz.
"When we found out he was going to play, a lot of people were very upset", he said.
Having snapped up their full allocation of tickets for today's World Cup play-off, around 3,000 supporters will cheer on the visiting team at Landsowne Road at 6 p.m.
Singing the Iranian national anthem in Dublin's Burlington Hotel yesterday was Ms Aideen Emdadian, a Longford woman married to Shahram, who is from Iran. Their children, Stacey (16) and Leonie (12), would be rooting for Iran, she said.
Mr Amid Alam and friends, originally from Iran but now living in Birmingham, waved their national flag as they toured Dublin in a horse-drawn carriage. "We've come to drink Guinness and see Iran beat Ireland", he said.
Mr Ali Sabetian, an Iranian who lives in Hamburg, Germany, said he was already looking forward to the next Ireland/Iran fixture in Tehran.
Meanwhile, the Football Association of Ireland (FAI) has given its backing to the National Anti-Racism Awareness Campaign's latest initiative.
A 25-foot banner proclaiming "Know Racism" will be carried on to the Lansdowne Road pitch at half-time today.
Three pages on Ireland's clash with Iran: SportsSaturday
Follow all the action from the Republic of Ireland v Iran match live on www.ireland.com/sports/soccer
