Mark Webber says increasing the speed of Formula One cars is meaningless if drivers are still unable to drive on the limit for an entire grand prix.
Regulation changes for next year hope to achieve a lap time increase of at least three seconds a lap with wider cars and tyres, while car weight is increasing by over 20kg. The current generation of cars have been criticised for being too slow and requiring too much fuel and tyre management, with McLaren's Fernando Alonso recently saying the pleasure of driving in modern F1 "has gone".
Webber, who won last year's World Endurance Championship with Porsche after switching from F1, does not think a speed increase means much if drivers cannot push all the time.
Asked about the imminent changes at the launch of Channel 4's F1 broadcasting team, Webber said: "The weight, they've got to keep an eye on that. You've got categories like that one I'm in now, we're right there [with F1 cars on weight] and we can [push] all day long, actually for 36 hours we can do in race trim.
"Formula One needs to be there on Sundays, not just when you talk about four or five seconds a lap in quali ... OK, that's fine, but these guys need to be on the limit.
"Downhill skiing ... look at all the other sports, they're on the limit. How do we bring that backwards from the athlete when they're not on the limit? That is something we've got to address and they're more than capable of doing that."
Webber can understand why the likes of Alonso speak out in frustration about the current state of Formula One and thinks the tyre management needed during winter testing in Barcelona highlights a wider problem.
"I think what these guys say is real, they're not inventing these comments. Especially the guys that have a position of some authority, I think it's important they talk. Come winter Barcelona is a horrible track for Pirelli because the degradation is massive ... that for a driver is like Rodger Federer hitting a tennis ball which is getting wetter and wetter and wetter and wetter.
"So when you are operating on that fine edge of a needle, which they do for not a huge percentage of the time, that is what a driver is trained up to do. That's the end point of Formula One to make sure you can go out and operate at that level for 80 or 90 percent of the operation and then there's a small slither that's not -- at the moment the ratio is a little bit inverted, the wrong way round, and that's when you get this frustration from the likes of Fernando who say the cars aren't fast enough."