Ferrari's Sebastian Vettel came out on top at Albert Park after a finely-poised F1 season opener that was effectively swung by Lewis Hamilton's tyre degradation not being as good as his rival's.

Although the tyre usage of the car has been singled out by Hamilton as a key area, one other issue that has come to light is the weight of the car.

With components having been bulked up this year because of the extra forces coming from the higher cornering speeds, plus engine parts being more robust now that there are only four power units for the campaign, the weight of the Mercedes is understood to have crept over the 728kg minimum limit.

The extra weight not only costs laptime, but teams like to be well under the minimum weight restriction with their basic car so that they can then position ballast in the right places to help with handling.

While Mercedes boss Toto Wolff would not confirm a report from Auto Motor Und Sport that the car was 5kg over the 728kg target, he did say that efforts were being made to bring the weight down.

"I don't want to go too much into detail but it's an area we can definitely improve," explained Wolff.

"With new regulations and the size of the cars, you need to balance out all the time between performance parts and the weight. And that's an ongoing exercise which we are doing."

Mercedes is not the only team that is facing headaches regarding weight.

Red Bull is understood to have found itself right at the weight limit thanks to the extra 5kg it has had to carry with Renault reverting to its 2016 MGU-K for the start of the campaign.

One of the reasons why Red Bull did not pursue a more complex suspension system after the FIA clampdown was because the weight of the design had started creeping up.

Force India too had big concerns about the weight of its car – ordering its drivers to go on diets after testing to help – but thinks it can address matters by the Bahrain Grand Prix.

Deputy team principal Bob Fernley told Motorsport.com: "We're already okay from a weight point.

"We're actually underweight but we're not enough underweight, so by Bahrain we will have enough of a variance there to be able to get the ballast where we want it. It's only a ballast issue."