US President Donald Trump on Saturday threatened his former advisor Elon Musk with "serious consequences" if the tech billionaire seeks to punish Republicans who vote for a controversial spending bill.

The comments by Trump to NBC News come after the relationship between the world's most powerful person and the world's richest imploded in bitter and spectacular fashion this week.

The blistering break-up – largely carried out on social media before a riveted public on Thursday – was ignited by Musk's harsh criticism of Trump's so-called "big, beautiful" spending bill, which is currently before Congress.

Some lawmakers who were against the bill had called on Musk – one of the Republican Party's biggest financial backers in last year's presidential election – to fund primary challenges against Republicans who voted for the legislation.

"He'll have to pay very serious consequences if he does that," Trump, who also branded Musk "disrespectful," told NBC News on Saturday, without specifying what those consequences would be.

He also said he had "no" desire to repair his relationship with the South African-born Tesla and SpaceX chief, and that he has "no intention of speaking to him."

Just last week, Trump gave Musk a glowing send-off as he left his cost-cutting role at the so-called Department of Government Efficiency (Doge).

But their relationship cracked within days as Musk described as an "abomination" the spending bill that, if passed by Congress, could define Trump's second term in office.

Trump hit back in an Oval Office diatribe and from there the row detonated, leaving Washington stunned.

With real political and economic risks to their falling out, both had appeared to inch back from the brink on Friday, with Trump telling reporters, "I just wish him well," and Musk responding on X: "Likewise." (AFP)