Australian Open players have been told not to feed mice at the quarantine hotel in Melbourne after one player complained of rodents in her room.
Yulia Putintseva, the world number 28, swapped rooms after finding a mouse but said her new room is also infested.
The 26-year-old is among more than 70 players and their entourages confined to their hotel rooms for 14 days.
Victoria state police minister Lisa Neville "encouraged" players to "minimise interaction" with the mice.
"As I understand, there may have been some feeding going on," Neville added, without giving further details.