Formula 1 says it is weighing up "several options" to replace the newly-axed 2021 Singapore GP.

Singapore promoter Colin Syn said organisers had no choice but to cancel the popular October night race "in light of prevailing restrictions for live events" in the city-state.

As for F1's "options" for a replacement, the speculation has already begun.

F1 CEO Stefano Domenicali seems determined to keep the race tally count at an unprecedented 23 this season, according to La Gazzetta dello Sport.

"The most likely hypothesis is to double-up the race in Austin, with the second one a week earlier on October 17," the authoritative Italian daily said.

"Another option is to try again for a race in Turkey, with a race in China the least likely scenario."

There are also fears that other races are facing Singapore-style cancellations, including Japan, Mexico, Brazil and Australia.

One source told us that "basically everything after Monza" is looking shaky.