Mercedes have introduced an “extra dimension” to the steering of their car for the new Formula One season, insisting it is within the rules.

World champion Lewis Hamilton was seen on an on-board camera using the so-called Dual Axle Steering (DAS) on the second day of pre-season testing in Barcelona on Thursday.

Hamilton could draw the steering wheel towards him on the straight and then release it before a turn, causing the wheels to turn slightly inwards.

It is thought the system will help better regulate tyre temperature.

Mercedes engineer James Allison was quoted on the F1 website as saying: “I probably won’t shed a great deal more light than what you saw on the TV but, yeah, we have a system in the car, it’s a novel idea.

“We’ve got a name for it, it’s called DAS, if you’re interested, and it just introduces an extra dimension for the steering, for the driver, which we hope will be useful during the year.

“But precisely how we use it and why we use it, that’s something we will keep to ourselves.”

Mercedes believe the system is perfectly within rules

“The rules are pretty clear about what’s permitted on steering systems and we’re pretty confident that it matches those requirements,” Allison said.