A Hobart DJ has admitted to headbutting former Australian prime minister Tony Abbott at the city's waterfront.
Astro Labe (38) pleaded guilty on Thursday in Hobart Magistrates Court to the charge of causing harm to a commonwealth official.
The court heard Labe followed Mr Abbott for about 250 metres and offered to shake his hand before "launching" into a headbutt on September 21.
Labe was arrested the next day and told police in an interview there was no one reason for his actions.
"I just hate Tony Abbot. I can't specify anything, crimes against humanity, yeah," the court heard he told police.
Magistrate Michael Daly questioned Labe's claim he acted spontaneously after the court heard he joked with friends about headbutting Mr Abbott on the day of the incident.
Labe's initial charge of common assault was upgraded to a federal offence that carries a maximum penalty of 10 years' jail.
His lawyer Craig Mackie said Labe, who moved to Tasmania 22 years ago, was not a person of violent disposition and had specifically "never headbutted anyone before".
"This can only be categorised as being at the very lowest end of the scale," Mr Mackie said in court.
Mr Abbott said he was left shocked and with a fat lip.
Labe will sentenced on March 22.
