Two-time major winner Victoria Azarenka says it is "bizarre" that fans need to be vaccinated to attend the US Open but not the players.

The 2021 US Open marks the first tennis tournament where fans must show their proof of COVID-19 vaccination in order to attend matches inside the Flushing Meadows venue. The decision was made less than 72 hours prior to the first matches at the US Open.

Azarenka, who defeated Italian Jasmine Paolini 6-3 7-6 (7-1) in the second round on Wednesday, said there was a double standard applied for fans compared to players who are not required to be vaccinated to play.

"I want to start this conversation between our players, because to me that's a bit bizarre that fans have to be vaccinated and players are not," three-time US Open finalist Azarenka told reporters.

"I think it's inevitable that it will be mandated at some point, like other leagues are doing.

"I don't see the point of stalling it, because I think we all want to be safe, we all want to continue doing our jobs, and I know there is a lot of discussions about it."

She added: "I hope that as an association we make the best decision for our business, for our health, for the tournaments and for the public."

On Saturday, Briton Andy Murray voiced his opinion that players need to be vaccinated, saying it is their responsibility as they travel the world to play.

Numerous top players including Novak Djokovic, Stefano Tsitsipas and Daniil Medvedev have previously spoken about their concerns about getting vaccinated.

Medvedev would not be drawn on Azarenka's comments after he defeated Dominik Koepfer 6-4 6-1 6-2 in the second round on Wednesday.

"Tough to answer this question," Medvedev told reporters. "I think everybody can have his own opinion.

"I understand why they did it to the fans. So far it has not been applied to the players. We as players, we can just follow the guidelines and the rules. That's all we can do.

"I think it's not for players to decide, because that's why we have governing bodies in tennis."