Sebastian Vettel has revealed his only dislike about the 2019 Ferrari, an "ugly" front wing.

As part of the rule changes, Formula 1 has returned to designs last seen in 2009 with a width that stretches right across the car and a simpler layout with only five elements and less of the parts that created 'outwash'.

Ferrari and Alfa Romeo both revealed concepts that try to recreate the effect, which directs air around the outside of the tyre, but Vettel questions the whole point of changing the wing in the first place.

"It's pretty ugly," he said on Monday. "It's too wide for me.

"I don't know why we've done that. A few years ago we made it smaller for overtaking, now it's been made wider for overtaking."

Some have wondered if Ferrari and Alfa might have gained an advantage with their radical interpretations of the new rules, but Red Bull isn't so sure.

"Worried is probably a bit extreme," he told Motorsport.com. "But it is interesting to see the different applications, and it will be interesting to see not what people have here on day one, but where they are in Melbourne in a month's time.

"We've looked at lots of different scenarios and, obviously, the route that we picked we feel is best to our concept. That's not to say it would work on a Ferrari concept.

"I'm sure it will evolve as the season gets underway. I don't think the cars that you see here, at the front end of the field, will be too similar to what you see in Melbourne."