WASHINGTON (AFP) - Tesla, the global leader in electric cars, was excluded from the White House event Thursday (Aug 5) where US President Joe Biden unveiled a big push for zero-emissions vehicles.

"Yeah, seems odd that Tesla wasn't invited," Elon Musk tweeted about the event that featured legacy American carmakers General Motors, Ford and Chrysler's parent company Stellantis.

The irascible entrepreneur has been a pacesetter in the industry, and Tesla last month reported its first-ever quarterly profit above US$1 billion (S$1.3 billion) on record deliveries.

But he also has a rocky record in relations with workers at his factories, including firing a union organiser and tweeting anti-union comments, which lead to a lawsuit by the United Auto Workers labour group.

Asked whether the snub was related to Tesla's non-union status, White House spokeswoman Jen Psaki told reporters the invited companies "are the three largest key players of the United Auto Workers. So I'll let you draw your own conclusion."

But she said the Biden administration welcomes the efforts of all manufacturers working on electric vehicles, including Tesla.

"I would not expect this is the last time we talked about clean cars, the move for electric vehicles, and we look forward to having a range of partners in that effort," Psaki said.

Interviewed on CNBC, Transportation Secretary Pete Buttigieg said he did not know why Tesla was excluded.

Musk responded by sharing a meme that read: "I'm not saying it's sabotage. But it's sabotage."