Barack Obama gives his take on Biden's disastrous US debate against Trump

The 81-year-old struggled to assert himself as he locked horns with his Republican counterpart on Thursday night.

The party has reportedly started exploring how it intends to remedy the matter, including the potential of replacing Biden as the Democratic nominee.

"'But this election is still a choice between someone who has fought for ordinary folks his entire life and someone who only cares about himself," Obama said as he slammed Trump.

The 44th president added: "Between someone who tells the truth; who knows right from wrong and will give it to the American people straight — and someone who lies through his teeth for his own benefit.

"Last night didn't change that, and it's why so much is at stake in November."

Hillary Clinton also shared support for Biden but noticeably did not mention the debate.

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She wrote on social media: "The choice in this election remains very simple.

"It's a choice between someone who cares about you—your rights, your prospects, your future—versus someone who's only in it for himself.

"I'll be voting Biden."

Following the horrific debate, the president himself admitted his performance was poor.

He told a crowd at a rally in North Carolina on Friday: "I don't debate as well as I used to" but "I can do this job".

Biden appeared to freeze during the debate and had difficulty stringing together strong cohesive statements.

CNN Chief National Correspondent John King said Democrats have declared "we have a problem" in private circles.