US president Joe Biden has appeared confused and “lost” on stage in a clip his political opponents have seized on to cast doubt over the leader’s mental acuity.

After delivering a speech on Wednesday (local time) at the Global Fund’s Seventh Replenishment Conference in New York, Mr Biden appeared unsure what to do.

The president wondered to the right of the stage before stopping and putting his hands out. He then lurched with his hands out before stopping again and standing still. As he appeared to interact with someone off stage, he looked unsure about what to do and whether or not to walk off.