A Hobart DJ who admitted headbutting former prime minister Tony Abbott was "'six-out-of-10" drunk at the time, a court has heard.
Astro Labe, 38, pleaded guilty on Thursday in Hobart Magistrates Court to causing harm to a commonwealth public official over the headline-drawing attack in September.
The court heard Labe was drinking at a Salamanca Place pub when he saw Mr Abbott and an adviser walking past.
Labe followed Mr Abbott for about 250 metres and offered to shake his hand before "launching" into a headbutt.
"I just hate Tony Abbott. I can't specify anything, crimes against humanity, yeah," Labe said during a police interview after being arrested the next day.
Labe told officers he was six-out-of-10 drunk.
Mr Abbott said at the time he was left shocked and with a fat lip and claimed the attack was linked to the same-sex marriage debate.
Labe will be sentenced on March 22 and could face up to two years' jail after his initial charge of common assault was upgraded to a federal offence.
"Obviously he made some admission to the press the day after the incident," Mr Abbott told 2GB on Thursday afternoon.
"The last thing that anyone should be subject to regardless of his or her position is an unprovoked assault, particularly unprovoked political assault."
Labe previously told media even though he was wearing a "yes" badge, the headbutt had nothing to do with marriage equality.
Defence lawyer Craig Mackie said Labe, who moved to Tasmania 22 years ago, was not a violent person and had "never headbutted anyone before".
"The harm caused was very minor," he said, adding his client's only previous convictions were for graffitiing.
"This can only be categorised as being at the very lowest end of the scale."
Prosecutor Jody Nunn is pushing for a jail term and said while Labe's guilty plea proved some contrition, his comments to national media on the day of the headbutt revealed the extent of his actual remorse.
She said Labe told reporters he "didn't think the headbutt was good enough" and that he did it because he "wouldn't get the chance" again.
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.
An eyewitness described the headbutt as "weak", the court heard.
