A social media post from US President Donald Trump lifted the Australian sharemarket and dropped the price of Brent crude oil below $US100, as markets reacted to the possibility of the Strait of Hormuz reopening.

The Australian sharemarket has climbed at the open while oil prices have tumbled on rising hopes of an end to the Middle East conflict.

The Australian sharemarket closed in the green while oil prices fell, amid rising hopes of an end to the Middle East conflict.