Billionaire entrepreneur and Tesla CEO Elon Musk said he was "disappointed" with US President Donald Trump's bill that pushes for a massive spending package, including multi-trillion-dollar tax breaks, stating that doing so will only "increase the budget deficit".

Speaking to CBS, Musk, once an avid supporter of Trump's policies, described it as a “massive spending bill” that increases the federal deficit and “undermines the work” of the Department of Government Efficiency, known as DOGE.

"I was disappointed to see the massive spending bill, frankly, which increases the budget deficit, not just decreases it, and undermines the work that the DOGE team is doing," Musk, who recently stepped back from running the Department of Government Efficiency (DOGE), said.

“I think a bill can be big or it could be beautiful. But I don’t know if it could be both,” he said.

Musk's interview with CBS came out Tuesday night.

Meanwhile, speaking in the Oval Office on Wednesday, Trump defended his agenda by talking about the delicate politics involved with negotiating the legislation.

“I’m not happy about certain aspects of it, but I’m thrilled by other aspects of it," he said.

The Tesla CEO was referring to the "One Big Beautiful Bill Act" that would fulfill Trump's vision for a new "Golden Age", led by efforts to shrink social safety net programmes to pay for a 10-year extension of his 2017 tax cuts.

The legislation also seeks to ramp up spending on border security, enforce Medicaid work requirements, and roll back clean energy tax credits.

The bill was passed by the House of Representatives last week and will now move to the Senate.