Renault has defended the legality of its 2018 car's exhaust layout.

At the rear of the yellow and black car, the engine exhaust is pointed upwards towards the rear wing, which has been reinforced with heat resistant material.

After running, the rear wing shows signs of heat charring, indicating that Renault is benefitting from outlawed exhaust 'blowing'.

However, technical boss Nick Chester said: "I have not heard any complaints.

"You can arrange the exhaust in various ways and we have just put it closer to the top of the bodywork.

"On most of the cars, the exhaust gas flow is directed more or less towards the wing, which is why we've developed a solution to make the most of the opportunities that the regulations allow.

"If the exhaust pipe is located where it is allowed to be, I don't see the problem."

The new season begins in two weeks' time in Melbourne.