A Tasmanian DJ is facing up to two years in jail after pleading guilty to headbutting former Australian prime minister Tony Abbott.
DJ Astro Labe, 38, plead guilty to causing harm to a Commonwealth public official after the incident on Hobart's waterfront on 21 September last year.
If the federal charge was heard in the Supreme Court Mr Labe could have faced up to 10 years in jail.
But it was agreed the case would be heard in the Magistrates Court, where the maximum penalty is two years' jail and a $25,000 fine.
On Thursday the Hobart Magistrates Court heard Mr Labe had been drinking with friends at a pub in Salamanca Place when he saw Mr Abbott walking with one of his advisors.
Mr Labe followed Mr Abbott about 250m before asking the former prime minister if he could shake his hand.
When Mr Abbott extended his hand Mr Labe grabbed it and headbutted him.
As he walked off Mr Labe was heard saying, "You f***ing deserved it."
Mr Abbott suffered a slightly swollen bottom lip.
Defence lawyer Craig Mackie asked Magistrate Michael Daly to consider the extent of injuries caused by the assault when sentencing Mr Labe.
"The harm caused was very minor," he said.
"No weapon was used. The incident was over in a second or two.
"Mr Abbott himself described it as a poor headbutt."
Prosecutor Jody Nunn said the injury suffered by Mr Abbott should not detract from the seriousness of the offence.
She said while a plea of guilty was evidence of some contrition, the magistrate should also consider the remarks Mr Labe made to media after he was charged.
Magistrate Michael Daly questioned Mr Labe's assertion it was a "spontaneous" act, as the court heard he joked about headbutting Mr Abbott earlier in day.
After the incident Mr Labe told media he was a "lone anarchist" that felt the need to headbutt Mr Abbott because he "didn't think it was an opportunity I'd get again".
Mr Labe also said although he was wearing a badge supporting the same-sex marriage campaign when he headbutted Mr Abbott, the act had "nothing whatsoever to do with marriage equality".
He will be sentenced in March.