Lewis Hamilton said the Baku track was not hard to learn but still tricky to drive. (Source: AP)

Triple Formula One world champion Lewis Hamilton has accused some rivals of ‘moaning’ about safety at the Baku street circuit that hosts Azerbaijan’s inaugural grand prix on Sunday.

“These drivers, they moan so much about so many things,” the Mercedes driver told reporters after going fastest in Friday’s free practice on a track that mixes very high speed straights with tight corners.

“It is really bumpy down the straight and you can’t really see turn one that well and it’s really hard, but that’s a part of racing,” added the Briton.

“These guys they want it to be smooth…smoother than ever, no vibrations and no bumps. They want to take all the character out of these tracks.”

German team mate Nico Rosberg, the championship leader, and Jenson Button, Hamilton’s compatriot and former partner at McLaren, both expressed concern on Thursday about the lack of run-off areas and the fast pit-lane approach.

Button, the 2009 champion, said it seemed the sport had gone backwards on safety.

“The track is pretty cool. There are just some safety concerns at a few places like the pit entry, which we have to look into,” Rosberg said on Friday.

The pit-lane entry comes off the 2km straight, now the longest in the sport, and enters a chicane some time before the speed limiter has to be applied.

Drivers argue that, given the importance of fractions of a second, drivers will only slow at the very last moment which could cause a big accident.

The governing FIA said on Friday it was making some modifications to the track after bolts holding down kerbs at turn six came loose during first practice.

Tyre supplier Pirelli raised the alarm after noting a high percentage of tyres had cuts caused by something sharp on the surface.

Hamilton, winner of the last two races and now just nine points behind Rosberg, said the track was not hard to learn but still tricky to drive.

“It’s very slippery out there. It’s quite Monaco-esque in terms of braking and how close the barriers are — but you’re arriving at much higher speeds,” he said.

“Otherwise it’s like a mixture of Valencia and Sochi with the smooth track surface and the style of the corners themselves. It’s a real challenge and I think it’s going to be tough for everyone over the weekend.

“It takes a lot of focus, which is something I like. I’ve enjoyed driving here today.”