A final agreement on Formula 1's engine regulations in 2021 could be reached by the end of this week, meeting a deadline set by the FIA.

The topic of changes to the power units in three years time has been a sensitive one, as it was the initial guidelines put forward that resulted in Ferrari chairman Sergio Marchionne issuing a threat to quit the sport.

Recently, talks entered the final stretch after Mercedes gave up their stance of wanting to maintain the MGU-H, which is set to be dropped as part of attempts to make the engines cheaper, simpler and noisier.

“It’s very complicated,” said race director Charlie Whiting last weekend in France.

“There’s meeting after meeting after meeting going on these things, and the reports I get on this appear to be very detailed, so they are going into fine detail.

“I’m fairly confident that it’s getting to the end of that process," he indicated. "And at the end of that process, we’ll have a far more detailed idea of what the power units will be in 2021.”

The governing body had set a deadline of June 30 to finalise the regulations, allowing manufacturers both current and potentially new, including Aston Martin and Porsche, time to develop the engines.

Something that Whiting was keen to stress though, was that it was the FIA and not those suppliers leading the way in the discussions.

“It might get talked about, but it’s not connected with the Strategy Group," he said, with a meeting of the World Motor Sport Council scheduled for next month.

“The manufacturers are involved in it, that’s why it’s taking quite a long time because they are to-ing and fro-ing on everything.”