Hamilton described the new focus on the issue as "almost a step backwards".

"It seems unnecessary to get into this. I am here to be an ally of the sport - we have bigger fish to fry," he said.

Hamilton, the driver who wears most jewellery out of the car, said that when in it he only wore "earrings and nose ring, which I can't remove".

For this race, Hamilton removed his earrings in the car and has been given a two-race exemption for his nose ring.

It is a new issue this year following the FIA's decision to change its race director in the wake of the controversy at last year's title-deciding Abu Dhabi Grand Prix. Wittich has taken a less flexible approach to many areas of the rule book than had been the case in the past.

Hamilton said he had reached out to FIA president Mohammed Ben Sulayem on Friday to try to resolve the stand-off but had not managed to get through.

"I am willing to sign a waiver to take the responsibility away from them if necessary," the seven-time champion said. "It is about individuality and being who you are.

"I did try calling Mohammed this morning and I think he was super busy but I sent him a message. I wanted to reassure him and said: 'I want to be an ally. I don't want to fight with you guys over this.'"

He added: "It has never been a safety issue in the past. If they stop me, we have a spare driver. There are lots of things to do here."

Before first practice in Miami, the FIA issued a further document emphasising that Mercedes "had not confirmed... that he is complying with the requirement to not wear any jewellery, in the form of body piercing or metal neck chains or watches".

Ben Sulayem was then seen going into a meeting with Mercedes team principal Toto Wolff.

The issue is highly unlikely to be taken so far as stopping a driver racing.

Hamilton was backed by colleagues, including Alpha Tauri driver Pierre Gasly.

The Frenchman said: "I do believe there are bigger things to focus on. I appreciate the FIA are looking after our safety. But in my case I am religious and there are things I have with me that I do not feel comfortable not having in the car.

"In the end, we are the ones who go out there and put our lives at risk and I do feel it should be a personal choice. I hope in the end we could find a better solution than this very strict one."

Mercedes have brought upgrades to Miami

Hamilton shrugs off critics

Hamilton has had a difficult start to season in a Mercedes team whose car is not competitive.

In the last race, he was lapped by world champion Max Verstappen after being stuck behind slower cars, which prompted Red Bull motorsport adviser Helmut Marko to say after the race that perhaps Hamilton should have retired at the end of last year.

Hamilton said: "I don't listen to those silly comments, to be honest. It has been interesting to see - there have been quite a lot of disrespectful comments I have seen over time, but it's to be expected.

"I just keep my head down. I know who I am. I love what I do.

"[We're] going through a tough time, didn't come out the starting blocks the way we wanted, but we're fighters and if you don't know that about me, you don't know me. I will keep doing my best to huddle up with the team and fight as hard as we can."

Will Mercedes improve with car developments?

Hamilton said he was not expecting a significant improvement in Mercedes' performance in Miami despite the team bringing their first serious development parts this season to the race.

There are new front and rear wings to try as the team bid to reduce what they believe is their biggest single problem - a high-frequency bouncing on the straights known as 'porpoising', which is promoted by aerodynamic disruption under the car.

But asked whether he expected the developments would improve Mercedes' competitive position, he said: "I don't anticipate that much change in that sense."