"The Red Bull is the only one we haven't seen realistically, it was obviously least year's car, but Red Bull always come out with a good car. I think they'll be competitive," said Button, speaking to Sky Sports.
"The Ferrari looks nice. It looks like they've worked on areas where they were weak and they've taken some risks in other areas. The car looks good.
"It's strange about Mercedes because the car, I would say it's beautiful. It's the most beautiful car, I would say the Mercedes. They might possibly be changing the sidepods. Surprised they didn't do that over the winter rather than into the season, but they obviously believe in the style they have for the first few races."
The 2009 F1 champion, added: "I look forward to that fight at the front, we all hope for that three manufacturers at the front fighting for the championship don't we, three teams – and I think we will get that at some point this season."
Button of course is himself preparing for a major test in 2023 - as part of NASCAR's Garage 56 entry for the Le Mans 24 Hour Race in June. He created a stir on Saturday when he paired up with Garage 56 team-mate Jimmie Johnson for a hilarious skit on cult movie 'Dirty Dancing'.