Police said 27-year-old Dominic Aku Jason from Eastern Highlands province was arrested yesterday and was in custody in Port Moresby
Police began investigating the man after he appeared to make a threat on social media, prompting a complaint by the prime minister himself.
The post reportedly stated 'PMJM You Need to Step Down Asap Before a Bullet Penetrate Your Head'.
Police Commissioner David Manning said the charge was very serious and must not be treated lightly given that it was a threat to kill a Prime Minister of a sovereign country.
He warned people who abused social media and threatened people, or spread false information, that police had strengthened their cyber-crime capabilities for monitoring and arresting people.