Naomi Osaka understands why people were offended by an advert's controversial portrayal of her but she insists her focus is solely on her upcoming Australian Open final.

Japanese noodle company Nissin, a sponsor of Osaka, apologised on Wednesday after whitening her face in an ad which displayed the US Open champion as an anime character.

Osaka, who was born in Japan to a Japanese mother and a Haitian father and moved to the United States when she was young, spoke publicly about the issue for the first time after defeating Karolina Pliskova in Thursday's semi-final.

A 6-2 4-6 6-4 success booked her place in a second grand slam decider, where she will meet Petra Kvitova, conqueror of Danielle Collins in straight sets.

"I'm just focused on this right now. I've gotten to the final of a slam, and that's sort of my main priority," Osaka told a news conference when asked about the Nissin ad.

"I've talked to them. They've apologised. For me, it's obvious, I'm tan. It's pretty obvious. I don't think they did it on purpose to be, like, whitewashing or anything.

"But I definitely think that the next time they try to portray me or something, I feel like they should talk to me about it.

"I get why people would be upset about it. The person that drew that, I'm not really sure, but I think he was the creator of [Japanese comic series] Prince of Tennis. I feel like you would have to do research on it, to see if he's ever done things like this before.

"I mean, to be honest, I haven't really paid too much attention to this. This is sort of the first time that anyone's asking me questions.

"I don't really want to say anything wrong at this point. I feel like I should do my research before I answer, if that's okay."

Turning her attention to Saturday's final against Kvitova, Osaka was well aware of the challenge of taking on a two-time major champion.

"I mean, we've never played before. I think to have the opportunity to play her for the first time in a final of a grand slam is something very amazing," Osaka said.

"I've watched her play the Wimbledon finals. I know what a great player she is. It's definitely going to be very tough for me."