Heavy rains have been disrupting the Spa-Francorchamps event all weekend, with Friday qualifying for tomorrow's grand prix delayed by 10 minutes.
While conditions were expected to get slightly more benign from Saturday onwards, fresh showers hit the Ardennes loop ahead of Saturday's sprint shootout, which sets the grid for the afternoon sprint race.
Thirteen minutes before the sprint shootout, which was due to start at noon local time, the start of the session was delayed a first time, awaiting a break in the conditions.
The FIA confirmed that if the sprint shootout is unable to go ahead, it will use the results from Friday qualifying to set the grid for the sprint race.
The session is due to start at 12:35pm local time.
Any grid penalties would still only be applied to the grand prix itself, meaning Red Bull's Max Verstappen would be able to start from pole despite incurring a five-place grid penalty for taking a fifth gearbox of 2023.
Haas' Kevin Magnussen would similarly be able to start from 13th instead of 16th after having impeded Ferrari's Charles Leclerc in qualifying.
The FIA added that "this would all be pending decision from stewards so is subject to change."
Little rain is expected for Sunday's grand prix, allaying fears of a repeat of the 2021 edition, which was hit by lengthy delays and halted after three laps behind the safety car.
F1's sensitivity to racing in the rain has been heightened after the recent fatal accident of Formula Regional driver Dilano van 't Hoff.
The 18-year-old Dutchman was killed at the start of this month after being hit on the Kemmel straight by a competitor while stationary.
The lack of visibility in the rain was a major factor in the accident.
In recent months FIA and F1 had already started taking steps to try and reduce the amount of spray that disrupts single-seater racing.
An initial Silverstone test with so-called sprayguards to reduce the amount of spray thrown up by the tyres has not yet produced satisfactory results.
The sprint race will start at 5:05pm local time, owing to the rules stating it cannot take place under four and a half hours from the start of the shootout.
