Dr Helmut Marko insists he has "no worries" about a recurrence of the brake problem that led to Max Verstappen's ultra-rare retirement in Melbourne.

The top Red Bull consultant says Verstappen, who nonetheless continues to lead the drivers' standings but only by 5 points, has coped well with the setback.

"Unfortunately, defects like that happen sometimes," said the 80-year-old Austrian. "In the meantime, Max has been skiing in Japan in the most wonderful deep snow in the world."

Marko, who was being interviewed by the Austrian newspaper Osterreich, was asked if Verstappen's skiing session contravenes a clause in his contract about engaging in dangerous activities off-track.

"I've already told you too much," he responded.

As for whether Red Bull has fixed the brake caliper problem that reportedly led to the fiery Melbourne failure, Marko told Laola1: "Max's brake broke and the exact cause is still being investigated.

"But it wasn't the caliper. It's more of an assembly issue, but that will be checked. I have no worries for Japan, that's not a problem," he insisted.

Marko also dismissed Sergio Perez's slow pace in Australia as the result of damage to the floor, with "the lack of downforce also increasing tyre wear".

"Suzuka is now a power track that suits us and Max is always great there," he insisted. "I'm very optimistic."

In Japan, Red Bull will be without a familiar face in the form of long-time chief mechanic Lee Stevenson, who according to Blick newspaper will instead be in the Audi-owned Sauber garage at Suzuka.

"He began his new job on Monday with a flight to Japan," reports veteran correspondent Roger Benoit.

McLaren, meanwhile, has parted ways with former Ferrari aero chief David Sanchez, a mere three months into his new role as car concept technical director. Team boss Andrea Stella temporarily fills the void.

"Upon our joint reflection, it became apparent that the role, responsibilities and ambitions associated with David's position did not align with our original expectations," McLaren explained in a statement.

Finally, Logan Sargeant will have a Williams chassis to race in Japan, having sat out Australia after teammate Alex Albon took over his car following a practice crash.

"The team trackside and back at Grove has really pulled together in an impressive way to repair the car and deliver it to the track on time," Alex Albon said on Wednesday, "which we are all hugely thankful for."