The reigning champion will have his work cut out if the prediction is accurate. Many in the paddock believe Ferrari looks the faster car however just how big their advantage is is up to debate.
Speaking ahead of his stint in the W10 on the final day of testing, Hamilton said he believes Mercedes will have to overcome a huge gap to their rivals.
"It's potentially half a second, something like that," he said.
"But we will be analysing a lot from this test and there will be some mods that we will try and implicate before the race.
"We don't obviously have a lot of time, but over this week we will hopefully gain another tenth just with our understanding of the car.
"The car is kind of old now, it's worn and torn, so we will have new components, all that stuff will come along.
"We really won't know because everyone has different power modes and fuel loads, so Melbourne will be the first time you get a sight of it and it's a good four races before you know just where you stand."