Mercedes could once again be about to pull away from its rivals in the horse power department.

Last year, Ferrari closed the gap on the German team, and also Renault and Honda made progress in 2018.

But La Gazzetta dello Sport reports that a brand new, "deeply redesigned" power unit has been produced at Mercedes' Brixworth engine headquarters, "keeping little" of the 2018 unit.

The Italian newspaper said Mercedes has made progress particularly in the area of energy recovery, accounting for 12 horse power extra for no more fuel consumption.

That is notwithstanding the fact that fuel consumption can actually increase in 2018, with the FIA giving the teams an extra 5kg of fuel to use per race.

Earlier, boss Toto Wolff revealed that a mistake had been made by Mercedes in the design of its 2019 engine.

"Unfortunately we ran into a minor mishap with the engine," he said.

"We thought the new concept would give us something else, but the guys in the factory are still ambitious so I am feeling optimistic.

"We will know more when the season starts in Melbourne," added Wolff.