Mercedes' driver Valtteri Bottas Photo: VCG

Mercedes boss Toto Wolff says reliability will be "fundamental" in deciding who emerges on top in the shortened Formula One season, with less margin for error due to the lighter schedule following the coronavirus lockdown.

Originally scheduled for 22 Grands Prix, with only eight tightly-controlled races have so far been confirmed with the season to get underway in Austria behind closed doors over the next two weekends.

Reigning champion Lewis Hamilton and his rivals hit the circuit on Friday for the first time since Barcelona testing in February, and Wolff warns they will need to hit the ground running.

"This new calendar and the coronavirus throw new challenges at us," said the 48-year-old Mercedes team principal.

The original opening race in Australia was cancelled at the last-minute after five crew members were quarantined when displaying symptoms consistent with COVID-19.

"Reliability is going to be a fundamental part of the first races. The cars have come out of the containers straight from Australia," Wolff said.

"There is not a lot of time to run them and we will be using every session to learn. 

"So a reduced race calendar is a challenge for everybody."

Mercedes also launched their innovative dual axis steering, which can widen or narrow the distance between the front wheels.

Mercedes will be wary of a slow start, however, after their drivers managed just fifth and eighth in 2019 at the Red Bull Ring following a rare double retirement the year before.

Ferrari's cars are the only ones not to have beaten their 2019 times in 2020 testing.

"We're not favorites, that's for sure," said the Ferrari driver Charles Leclerc.

Team Haas chief Gunther Steiner also said it would be crucial not to make any early mistakes.

"That is one of the things that we focus on, not to make mistakes," he said. 

"Every mistake you make counts more because you have got fewer opportunities to make up for it.

"No mistakes will not happen, but that is what we focus on to keep consistent."

Steiner said Haas had nothing new to match Mercedes' dual axel, but suggested innovations could be sometimes problematic.

"That's part of why we decided we are not going to develop big upgrades or anything. Because every time you make an upgrade, it takes time to learn about it and how to use it," the Italian added.

"Having not only fewer races, but in a short space of time, one of the most important things is not to make mistakes at any time."