According to earlier official figures, the floods left 18 dead, 200 hospitalised and eight more missing.
A representative from the regional emergency services said that the number of those hospitalised had risen to 221, including 41 children.
He added that the list of missing people included a child.
A state of emergency was declared in the Tulunsky, Chunsky, Nizhneudinsky, Tayshetsky, Ziminsky, and Kuytunsky districts of Irkutsk.
Regional as well as federal authorities are making efforts to provide the necessary aid to those affected by the disaster.
On Tuesday, the Federal Medical and Biological Agency set up a mobile hospital in the region to provide medical assistance.
Russian President Vladimir Putin visited the area on Sunday on his way back from the G20 summit in Japan and ordered the military to join the relief efforts. Putin said he would hold a meeting about the situation in the region in Moscow on Wednesday.
The Russian branch of Greenpeace said Tuesday that the flooding in the region was a consequence of climate change. Scientists from the Irkutsk State University later suggested that an anomalous development of atmospheric processes could have caused the flooding.