Many are expecting the factory Mercedes team and its engine customer Williams to run away with the first race of the new season in Melbourne, after leading the way on one-lap pace and race simulations during the final pre-season tests in Bahrain.
Button says the latest generation of F1 machines have more torque than their predecessors, increasing the difficulty for drivers in managing wheelspin.
And the 2009 world champion reckons the unique demands of the Sakhir circuit in this regard might have created a slightly false impression of Mercedes' and Williams' advantage.
Melbourne won't set the 2014 tone
"Bahrain is possibly the worst circuit for it [difficulty applying throttle without wheelspin] because it was hot and the layout makes it very difficult to apply power," he said.
"I think it's a unique circuit, so I think it'll be a lot closer in laptimes for the whole pack than what we saw in testing.
"That's why I think you're not going to have such a big margin between the top two teams and the rest.
"When you look at the times of the Williams and Mercedes they are going to be very difficult to beat - if reliability wasn't an issue, and strategy also.
"[So] I still think they can be challenged this weekend."
Button has expressed his concern that McLaren's MP4-29 is not fast enough to fight at the front at the start of the season, but he thinks reliability will be more important than speed in the early part of the campaign.
Cause for concern at McLaren in Bahrain test
"You've got to finish the first three races really," he added.
"If you can do that you're going to take home some reasonable points, even if you don't have the quickest car.
"As a team we want to win races. I'm not sure we'll be able to do that this race but you never know.
"The conditions look very up and down and it's not all about outright speed.
"There are other things that will be thrown in this weekend that will make it a little more complicated."
- Sports & Recreation
- Motor Racing