Mercedes boss Toto Wolff predicts radio controversy at Singapore GP

Teams are no longer allowed to issue instructions to drivers to help with either car or driver performance.

And although the move was supported by a number of teams after discussions in F1's Strategy Group at the Italian Grand Prix, Wolff thinks the new approach will not be so straightforward to implement.

"This is a complex and controversial decision which will require a significant effort from the teams to understand how best we can work around it," said Wolff in a team preview on Friday.

"The directive is not yet fully clear and there will inevitably be some controversy, so it will need further clarification as to how much the essential on-track procedures will be affected - particularly before the start of the race."

Despite Wolff's uncertainty over start procedures, the FIA has indicated that it will not tolerate any formation lap instructions - such as advice on tyres, brakes, gearbox and clutch.

An FIA spokesman said: "None of this would be allowed. This is exactly what the FIA thinks is going to infringe Article 20.1."

The closeness of the battle between Mercedes duo Nico Rosberg and Lewis Hamilton has highlighted how much drivers are relying on team information this year - as both men have benefited from input from the pit wall about where they are losing out.

Rosberg even asked his engineers for 'driving style' advice during Italian GP practice in a bid to gain assistance on improving his lap time.

It is this reliance on the pit wall that has left the sport's chiefs frustrated about drivers appearing to be puppets, which is why they have backed the change.