US President Joe Biden promised "consequences" for Saudi Arabia after a Riyadh-led coalition of oil-producing nations sided with Russia to slash output.

The 13-nation Opec cartel and its 10 allies headed by Moscow angered the White House last week with its decision to cut production by two million barrels a day from November, raising fears that oil prices could soar.

"I'm not going to get into what I'd consider and what I have in mind. But there will be – there will be consequences," Biden told CNN when pressed on possible responses in a rare televised interview.

The Democratic leader did not reveal what options were being considered, but the White House had made clear earlier that Biden was reassessing ties between the allies.

"I think the president's been very clear that this is a relationship that we need to continue to re-evaluate, that we need to be willing to revisit," National Security Council spokesman John Kirby said.

"Certainly in light of the Opec decision, I think that's where he is."

The Opec move was widely seen as a diplomatic slap in the face, since Biden travelled to Saudi Arabia in July and met with Crown Prince Mohammed bin Salman, despite vowing to make the kingdom an international "pariah" following the murder of journalist Jamal Khashoggi.

It also comes at a sensitive moment for Biden's Democratic Party, as it faces November midterm elections with rising consumer prices a key Republican talking point.

Saudi Arabia has defended the planned production cuts, saying the priority of Opec+ was "to maintain a sustainable oil market".

On Tuesday, Saudi foreign minister Prince Faisal bin Farhan told the Al-Arabiya channel that the move "was purely economic and was taken unanimously by the [organisation's] member states".

"Opec+ members acted responsibly and took the appropriate decision," he said. (AFP)