Nov 14 (Reuters) - As Tesla’s electric-vehicle sales have flattened this year, CEO Elon Musk has increasingly staked the company’s future on his vision for self-driving robotaxis, despite the massive technological and regulatory obstacles in delivering them.

Now Musk - as one of President-elect Donald Trump's biggest backers - may have the influence to help break through those regulatory roadblocks.

“If there’s a department of government efficiency,” Musk said, “I’ll try to help make that happen.”

On Tuesday, Trump tapped Musk and another ally to lead such an entity, which is not a government agency. It remains unclear how the organization will function.

Musk's sway is likely to extend beyond efficiency. The billionaire, who gave at least $119 million to a pro-Trump group during the campaign, is expected to influence the president-elect’s pick for the next Transportation Department secretary, according to a person close to Musk and Trump’s transition planning. That department, which includes the National Highway Traffic Safety Administration (NHTSA), regulates automakers and could push through significant changes to the self-driving rules at a national level.