Federal Opposition Leader Tony Abbott has thrown his support behind the incumbent, Senator Gary Humphries, in what is shaping up to be a bitter fight for the Liberals' ACT Senate preselection.
ACT Opposition Leader Zed Seselja is seeking preselection for the No.1 spot on the territory's Liberal Senate ticket for this year's federal election.
He announced his resignation as Liberal leader on Monday, saying he was challenging Senator Humphries for the prized upper house seat.
"I'm taking this step because I think I'm the best person to represent the ACT and the ACT Liberal Party in the Federal Parliament," Mr Seselja said.
"I have a lot of respect for Gary Humphries. I respect the contribution that he continues to make. I don't take anything for granted."
Before the Christmas break, Mr Seselja said he had no intention of making a move into federal politics.
Asked on Monday if he had already secured the numbers to roll Senator Humphries, Mr Seselja said he did not know.
"I certainly believe that I have a strong level of support within the party. As to the exact numbers, I don't know and that will become apparent in the coming days," he said.
It is believed Mr Seselja has the numbers to win preselection, but he will not be able to count on the support of the federal leader of the Liberal Party. In response to questions by Fairfax Media, Mr Abbott gave his support to Senator Humphries.
"As a former chief minister, Gary has been an outstanding advocate for the ACT and contributor to my shadow ministry," Mr Abbott said. ''He has my support."
Mr Seselja did not respond to Mr Abbott's statement of support for Senator Humphries, but a senior ACT Liberal Party source said there was no surprise in the comment; federal leaders had to be seen to be publicly backing their incumbent MPs.
''But there will be no captain's pick,'' the source said.
Mr Abbott does not have a vote in the ACT preselection, and it is yet to be seen if the 400 or so local members will defy their federal leader.
During his address to the National Press Club last week, Mr Abbott said he was very happy with his shadow ministry and that all of his current front bench should expect to keep their responsibilities if he wins government.
As a shadow parliamentary
secretary, Senator Humphries is a member of Mr Abbott's frontbench.
He is the first ACT Liberal to be a member of any Coalition frontbench in the Federal Parliament.
Senator Humphries said he was pleased that Mr Abbott had given his support for his candidacy.
"I'm honoured to have the support of the federal Leader of the Opposition in seeking Senate preselection for the Liberals in the ACT," he said.
"I'm looking forward to the opportunity to be a member of the frontbench of a Coalition government led by Tony Abbott."
Senator Humphries said he would be "fighting vigorously" to win the preselection contest.
Should Mr Seselja win, he said, Canberra would lose a voice on Mr Abbott's frontbench.
"There is a particular challenge facing the people of Canberra in the next three years, particularly if there is a change of government," Senator Humphries said.
"Canberra is going to be facing very heavy pressures. We know that this city will be the subject of some very tough decisions by an incoming government, as it has been of the present government over the past few years.
"Canberra will need a champion - a person prepared to go into the offices of ministers in that government and act as its advocate and say 'I am here to stand up for the people of my city'.
"I want to make sure this city is looked after, even when hard decisions have to be made about reining in federal expenditure."
Senator Humphries said that while he supported the next federal government in doing what it needs to do to bring the budget back into surplus, that should not be done at Canberra's expense.
A professor in politics at the Australian National University, John Warhurst, said the preselection battle could be "quite a barney".
"Zed [Seselja] has obviously built up some momentum and has the support of a lot of younger Liberals," Professor Warhurst said.
"But Gary Humphries has been around a long time and he has a lot of support too."