A consortium of investors led by billionaire Elon Musk is reportedly offering $US97.4 billion ($A155.2 billion) to buy the nonprofit that controls artificial intelligence startup OpenAI.

The offer, reported in the Wall Street Journal, intensifies a longstanding battle between OpenAI CEO Sam Altman and Musk over the startup's future at the heart of a boom in generative AI technology.

Musk's attorney, Marc Toberoff, said he submitted the bid to OpenAI's board on Monday, according to the report.

"It's time for OpenAI to return to the open-source, safety-focused force for good it once was," the newspaper cited Musk as saying in a statement provided by Toberoff. "We will make sure that happens."

OpenAI, Musk, Toberoff and OpenAI-backer Microsoft did not immediately respond to Reuters' requests for comment.

The WSJ reported that Musk's AI company, xAI, backs the bid. If a deal is reached, xAI could merge with OpenAI.

Musk co-founded OpenAI with Altman in 2015 but left before the company took off. He later founded the competing AI startup xAI in 2023.

OpenAI is now trying to transition into a for-profit from a nonprofit entity, which it says is required to secure the capital needed for developing the best artificial intelligence models.

Last year, Musk filed a lawsuit against OpenAI and Altman, saying that OpenAI's founders originally approached him to fund a nonprofit focused on developing AI to benefit humanity but that it was now focused on making money.

With AAP.