Jenson Button has warned there are some circuits where GP2 times will be close to the 2014 F1 cars this season.

Asked if the 2014 cars will be much slower than their predecessors, Button replied: "Yes, we will be.

"We've used the medium so far which we think is half a second slower than last year's medium. The cars are also heavier, which is about 1 or 1.2 seconds through weight, so that's 1.6 or 1.8s already just from those two changes.

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"[GP2] will be a lot closer on certain circuits. High-speed we will be quicker but we won't be that much quicker. But then again it's the first test with a very new package. Last year was hardly a change at all in terms of the regulations so at the first test we were always going to be quite quick and then you improve for the first race but it's not a massive chunk.

"Now, when we get to the first race everyone is going to be much quicker. And then three races in there will be another chunk in terms of lap time - another second or something - so by the end of the year we might not be that far off; a couple of seconds. I think it will be pretty good when we get a handle on where we are."

The fastest time of the first test at Jerez in 2013 was a 1:17.879 by Ferrari's Felipe Massa, compared to a 1:23.276 set by Kevin Magnussen for McLaren this year.