Tomorrow could be the most dangerous day of this century, Sky News host Andrew Bolt says.

“Nancy Pelosi, speaker of the US House of Representatives, second in line to take over from the president if he dies, has confirmed she will fly tomorrow to Taiwan,” Mr Bolt said.

“Taiwan is an island off China, and a democracy.

But the Chinese dictatorship says it's actually a renegade province, Chinese territory.

Mr Bolt said China’s army “will act” if Ms Pelosi visits the island nation.

“In fact, China has been conducting live fire exercises near Taiwan, and on Sunday sent one of its aircraft carriers from the south, apparently towards Taiwan," he said.

“US warships are now poised behind Taiwan to offer protection.”

Mr Bolt discussed the issue with The Australian’s North Asia correspondent Will Glasgow.