Greens candidate Simon Sheikh at the National Press club.

Greens candidate Simon Sheikh at the National Press club. Photo: Melissa Adams

The Greens' ACT Senate hopeful for this year's federal election says he has taken no interest in the bitter preselection struggle engulfing the Canberra Liberals.

Former GetUp! activist Simon Sheikh says it makes no difference to him who he faces in the fight for the territory's second seat in the upper house when the nation goes to the polls in September.

The Greens and the Liberals have battled it out for the seat in the past two elections with incumbent Gary Humphries coming out on top both times.

The 10-year Senate veteran is being challenged, for the first time in his upper house career, by former local leader Zed Seselja and the party has descended into an ugly war of words over the management of the preselection process.

But Mr Sheikh said on Tuesday that he had no preference between the two candidates and instead went on the attack against both Liberals.

"I often get asked if I would prefer one candidate over another from the Liberal Party and the answer is, I wouldn't because Gary Humphries couldn't get Tony Abbott to change his breakfast order and Zed Seselja is Tony Abbott-lite," the Greens candidate said.

"The only way to protect Canberra families from Tony Abbott's job cuts is to vote for the Greens."

Asked if he thought the Liberal bloodletting was helping his own chances, Mr Sheikh said the election was a "long way out."

"We're a long way out from the election but presumably that's at the back of their minds," he said.

''We don't take much of an interest in it, our campaign is already up and running. Just tonight [Tuesday], at the Palace Electric Cinema, we're having our first meeting and more people are coming out tonight to commit to volunteering for our campaign than are voting in the Liberal Party preselection.

"The rest of the community are getting on with their everyday lives or with the political campaign they are volunteering with."

Mr Sheikh said 360 potential Greens activists had pledged to attend Tuesday evening's event in Acton with former Greens national leader Bob Brown.

Senator Humphries shot back at the Greens, branding the party "pathetic".

"Today [Greens leader] Christine Milne announced the end of her formal alliance with Julia Gillard but then went on to say that the Greens still guarantee supply and confidence - that's pretty pathetic even by the Greens' standards," he said.

"Let's not forget that the Greens have voted with the Labor Party for budget measures that have seen thousands of public servants lose their jobs. The Greens' crocodile tears aren't washing with voters.''

Mr Sheikh described his party leader's move as the end of the "happy relationship" between the two parties.

"What we've said is that it's the end of any happy relationship," he said. ''In Parliament, we've always stood for our own values and our own policies but we have tried to be friendly in our approach to delivering stable government. From today we will continue to deliver stable government but we will be even stronger advocates because there is such a great difference between the Greens and the Labor Party, and an even greater difference between the Greens and the Liberal Party."