None of the players concerned are understood to be members of the current world top 16, meaning they would have been scheduled to take part in the qualifying rounds which start on July 21.
Earlier this week, reports in China suggested up to 10 players had declined the opportunity to take part in the tournament, citing concerns regarding coronavirus and quarantine regulations.
Former finalist Ding Junhui, who missed last month's Coral Tour Championship, has indicated he will take part, while Yan Bingtao, the other Chinese player in the top 16, is based in Sheffield and unaffected.
But former world number five Marco Fu, three-time women's world champion Ng On-yee, and Zhou Yuelong, who beat Mark Allen in the first round last year, are reportedly among those who have withdrawn.
In a statement, World Snooker Tour noted: "Several players have indicated that they have decided not to travel to the UK and the draw for the qualifying rounds will be made after the entry deadline which falls on July 6."
Despite continuing uncertainty over quarantine regulations which may impact the respective arrivals of overseas players, WPBSA chairman Jason Ferguson said he was confident the process will run smoothly.
Ferguson said: "Since the beginning of the coronavirus pandemic we have worked tirelessly to ensure that every player has the chance to play in the Betfred World Championship.
"We knew this would be a huge task in the climate, but not an impossible one - and we have now reached a point where players can make their own choice. We have done everything we can to support our playing membership.
"We appreciate that a small number have indicated their decision not to come to the UK, but the vast majority will compete and, without question, the show must go on."
