The local authorities in Rome are discussing the situation, as Lazio-Milan could be played later today after flash floods.
Several different committees are coming together to debate what is to be done with this Serie A match.
It was due to kick off at 14.00 UK time (13.00 GMT).
The Prefecture was meant to give the final decision at 11.00 UK time and made it clear the game could not go ahead because of public safety.
Roads are flooded and Metro lines are closed down, while there are also electricity blackouts in several areas.
There are now a few different options, as Milan and Lazio have been told to remain in the team bus.
It could go ahead as planned, but without fans, or have the kick-off delayed to 17.00 UK time (16.00 GMT).
The Stadio Olimpico pitch itself is not the issue, as that has been covered with plastic sheets since yesterday, but public safety cannot be guaranteed in these circumstances.