Formula One says it is investigating claims of "unacceptable" harassment reported by some fans attending the Austrian Grand Prix weekend.

Posts on social media complained of sexist, racist and homophobic slurs at the sold-out event at Spielberg's Red Bull Ring.

In a statement on Sunday, F1 said it had been made aware of "reports that some fans have been subject to completely unacceptable comments by others at the event."

"We have raised this with the promoter and security and will be speaking to those who have reported these incidents and are taking this very seriously," the statement continued.

"This kind of behavior is unacceptable and will not be tolerated and all fans should be treated with respect."

Seven-time world champion Lewis Hamilton raised the issue on his Instagram page.

"Disgusted and disappointed to hear that some fans are facing racist, homophobic and generally abusive behaviour at the circuit this weekend," he wrote.

"Attending the Austrian Grand Prix or any GP should never be a source of anxiety and pain for fans and something must be done to ensure that races are safe spaces for all," his post continued.

"Please, if you see this happening, report it to circuit security and to F1. We cannot sit back and allow this to continue."

An estimated 50,000 Dutch fans, many dressed up in "Orange Army" t-shirts, have descended on Spielberg to support world champion Max Verstappen.

The behavior of some of the Red Bull driver's supporters was already called into question when cheers rang out after Mercedes duo Hamilton and George Russell crashed in qualifying Friday.

Both Hamilton and Mercedes team principal Toto Wolff criticized that behavior, as well as the booing Verstappen, had received at Silverstone the previous weekend.

"It's just mind-blowing that people would do that, knowing how dangerous our sport is," Hamilton said.

"You should never cheer someone's downfall or someone's injury."

"It's not very sportsmanlike," Wolff agreed.

"Fans cheering when a driver crashes out, you should question the attitude and understanding of sport."

"Booing is not good either," said Wolff.

"As teams, we fight, but booing is a personal attack on a driver. Fans should put themselves in the same position."