Rybakina 'focused' on Australian Open after coach controversy
The sixth-seeded Kazakh had wanted to bring Vukov back into her coaching team for the first Grand Slam of the year.
But the Croat is currently under a provisional suspension "pending an independent investigation into a potential breach of the WTA code of conduct," said the women's tennis governing body.
Vukov, who helped Rybakina win Wimbledon in 2022, was reported to have used harsh and abusive behaviour towards players. He denies any wrongdoing.
Rybakina defended him when questioned by reporters on the eve of the first Grand Slam of the year.
"I don't agree with a lot of things what WTA do in the sense of my relationship with Stefano," said Rybakina, who lost in the 2023 Australian Open final to Aryna Sabalenka.
"I have never made any complaints or any of these things. I always said that he never mistreated me.
"Definitely not the ideal situation. But as I said, my goal here is to focus on the matches. This is what I'm going to do.
"I don't really want to speak about this more."
Rybakina faces a first-round match against 16-year-old Australian Emerson Jones, the world junior number one tipped to follow in the footsteps of former Melbourne Park champion Ash Barty.
"I think she's definitely a good player," said Rybakina of the youngster, who will be making her Grand Slam main draw debut after being awarded a wild card.
"She's a good player, dangerous player. Especially when you're young, you have nothing to lose. And she's at home.
"I definitely take it as a very tough opponent because you never know what to expect."