Formula One world champion Lando Norris and McLaren teammate Oscar Piastri failed to start the Chinese Grand Prix on Sunday due to electrical issues.

Champions McLaren discovered an electronics issue with Norris's car before it was due to head out on track while Australian Piastri's car was then pushed off the grid and back to the garage.

Mechanics removed the floor on Norris's car, with the team still working to resolve the problem as the grid closed for the second race of the season.

The Briton had qualified sixth, with Piastri fifth but both grid positions were left empty.

"It's an electric issue on the power unit," Piastri told reporters shortly after the race start, "which I think was the same for Lando, but it's not the same electrical issue.

"It's been a while since I've watched two grands prix on TV," added the Australian, who crashed out of the season-opener in Melbourne on his reconnaissance lap before the start of the race.

Piastri won in China last year from pole position.

"They're (the power units) just incredibly complex, and there's so many rules on the power units that you sometimes change one thing and it has a very unintended consequence somewhere else," Piastri added.

His British teammate said he got into his car while mechanics worked on it in case there was a red flag early on, though at no point did it look race-ready, he conceded.

The Williams of Alex Albon suffered a hydraulics problem on the way to the grid while Audi's Gabriel Bortoleto also failed to start, leaving 18 cars on the grid.

Mercedes locked out the front row with 19-year-old Italian Kimi Antonelli the youngest ever grand prix polesitter ahead of championship-leading teammate George Russell.

-Writing by Alan Baldwin in London, editing by Peter Rutherford/Reuters