New Zealand-born actor Russell Crowe has turned heads on social media with his praise of Jacinda Ardern, saying NZ and Australia should merge into one country so the Kiwi Prime Minister can lead both.

Russell Crowe and Jacinda Ardern. Source: 1 NEWS

Mr Crowe responded to a cheeky tweet made by Australian journalist Jonathan Green, who claimed Ms Ardern as the "Prime Minister of Australia" in honour of the "pavlova/Russell Crow tradition".

Mr Crowe obliged, saying Ms Ardern is "awesome".

"Is it time to make Australia and New Zealand into one country with Jacinda Ardern as PM?

"Not trying to be controversial... just practical."

The suggestion comes after a productive week in New York from Ms Ardern where she spoke at the United Nations General Assembly and appeared on multiple US television shows to promote New Zealand.