Ross Brawn has named three leading contenders to complete Formula 1's planned 23-race calendar in 2021.

"Obviously we are sorry that we cannot go to Vietnam again, but we will find a strong candidate," said F1's sporting boss, referring to the 'to be confirmed' host listed alongside the April 25 race date next year.

Italy's La Gazzetta dello Sport asked Brawn about recent comments made by Italian racing chief Angelo Sticchi Damiani, who said Imola is pushing for the slot.

"We saw a good race in Imola this year, as we did in Portugal and Turkey, so everything is open," Brawn said. "Let's see how the issue develops."

He admitted that after Formula 1 profits were slammed by the corona crisis this year, economic considerations will play into the final decision.

"Yes, there is no doubt that we want to return to a normal situation next year and so there will be a strong consideration from a commercial point of view," said the Briton.

"Some countries will be in a better position than others because they will be able to make better commercial offers, and we must take this into account. We need to get back to normal financial levels as quickly as possible.

"So yes, the commercial aspect will have a greater weight than it did this year."

Some think F1's plans for an unprecedentedly-long 23-race calendar are fanciful amid the ongoing pandemic. The season-opening host Melbourne, for instance, is only just coming out of a strict lockdown.

"Australia is currently enjoying a good situation from a covid point of view," Brawn insists.

"They haven't decided yet how to manage the tennis (Australian) Open, but things are changing rapidly and I am optimistic.

"I believe Australia understands that F1 knows how to behave responsibly when visiting a country. And then the vaccine will come," he added.

"I remember when I started working in F1, we were used to getting vaccinated to go to some countries. Doing it again now would be a reasonable compromise."

As for the location of the single winter test early next year, amid rumours it will either be Barcelona or Bahrain, Brawn answered: "We are discussing it with the teams now and will decide in a couple of weeks."