Formula 1 is still not ready to confirm the accuracy of a leaked version of next year's race calendar.

Recent reports suggested the 2021 schedule will have an unprecedented 23 grands prix, and now media sources have published a version of it - starting in Australia on March 21 and ending in early December in Abu Dhabi.

The calendar does have 23 race dates, but political problems in Vietnam mean the scheduled April 25 event will likely now be replaced by Imola, Istanbul or Portimao.

Toto Wolff hopes that F1 has learned from 2020, when some more traditional circuits stepped in amid the corona crisis to give the sport an alternative calendar.

"I do not agree with this tendency towards circuits that look like large supermarket parking lots," said the Mercedes boss. "We need circuits on which mistakes are really punished."

Istanbul Park, to host this weekend's Turkish GP on a challenging venue, is clearly hoping to secure that vacant slot in 2021.

"I am trying to retain it," promoter Vural Ak confirmed to the Anadolu news agency.

"We are in talks to hold the Turkish GP next year as well. It will likely be finalised very soon. My goal is to make this race a regular feature," he added.

Barcelona, meanwhile, has a May 9 race scheduled despite not yet signing a contract with Liberty Media, while Interlagos is still on the 2021 calendar even though Rio de Janeiro has launched a rival bid.

Formula 1, though, is not ready to confirm the leaked information.

"We will not comment on the provisional calendar until it is made public and confirmed," a spokesman said.