The delay in the signing of Lewis Hamilton's new contract is triggering a new round of rumours.

Some believe that the reigning world champion is making Mercedes "sweat" to exert his power or negotiate more money, while others think he may quit Formula 1.

"He is powerful enough and a precious commodity in the sport and maybe is just making them wait and sweat a bit," 1996 world champion Damon Hill told The Sun.

"But I wonder if Nico Rosberg's retirement weighed on his mind a little bit. When you are an F1 driver, you hanker for the days when you can escape from it."

Mercedes team chairman Niki Lauda denied speculation that Hamilton is delaying simply for more money.

"There is nothing more lucrative than if he continues to win. That's all negotiated," he told Bild am Sonntag.

The Hamilton holdup is having a knock-on effect in the driver market, with Daniel Ricciardo for instance linked with both Mercedes and Ferrari.

"In an ideal world, Ricciardo would have already signed," said Red Bull boss Christian Horner.

Hamilton currently leads the 2018 driver rankings by 17 points.