Dutch GP boss Jan Lammers says it is too early to say September's scheduled event at Zandvoort will have to proceed without spectators.

Last year, Zandvoort opted out of the 'ghost race' scenario amid the pandemic because the structure of the event was always planned for the mass attendance of Dutch fans.

Medical experts are now warning that the situation may be no different in 2021.

"Even if most of the Netherlands will have been vaccinated by September, it is still a very big risk if you are all sitting on top of each other with so many other people," said Ger Rijkers, who according to Algemeen Dagblad newspaper is an immunologist.

He said even rapid covid testing of spectators at the gate will not be sufficient.

"Even if it takes 5 minutes per person, you'd still be doing it all day," said Rijkers. "I can only foresee problems."

However, he said the 'ghost race' scenario may be viable for Zandvoort, especially after Formula 1 "proved itself as a TV sport" in 2020.

Dutch GP boss Lammers, however, is not ready to concede that if the race takes place, it will be behind closed doors.

"We cannot afford to cry before we are in pain," the former F1 driver said.

"We are still happy with our date of September 5. And we hope that the good news will replace the bad news in the near future."

Therefore, any talk of a 'ghost race' is premature, Lammers added.

"When there is a specific question in that direction, then we would have something to think about," he said.