It would be unusual as Mr Sanders is expected to lose out for the Democratic nomination to Hillary Clinton. She would be left on the sidelines if the event happens.

Mr Trump said: "I would love to debate him, it would be a dream. It would be if we could raise $10 to $15 million. It's got to be in a big arena.

"I've had a couple of calls from networks already. It's true I would love to debate Bernie. I would say it would have to be something over $10 million."

Mr Trump added: "If I debated him we would have such high ratings. I think I should take that money and give it to some worthy charity."