The change was mandated on Wednesday by Opposition Leader Tony Abbott, who criticised the Greens’ ‘‘fringe economic policies’’.

In the 2010 election, the Greens’ Adam Bandt won a lower house seat in Melbourne on the back of Liberal preferences. In that election, Canberra Liberals put the Greens ahead of Labor in the ACT Senate vote.

ACT Liberal Zed Seselja said he agreed with Mr Abbott and the Greens should be preferenced last in the federal election.

Mr Seselja, the former ACT opposition leader, is seeking to hold the Liberals Senate spot against a strong challenge from the Greens’ Simon Sheikh.

‘‘I think it’s important that you state these principles before an election and you stick to them. I don’t think people want to see these sort of deals.’’

Mr Sheikh said he was encouraging voters to put the Greens first and decide themselves on preferences.

‘‘Canberrans are walking away from both the old parties because they know that the only way to stop Tony Abbott from gaining total control of both houses of Parliament is to vote Greens in the Senate,’’ he said.

‘‘The only extreme possibility at this election is the extremely concerning possibility that Canberra will be pushed into recession by the job cuts planned by the two old parties.’’

In the 2010 election, Labor’s Senate group voting ticket received 93,639 first preference votes, with 76,463 for the Liberals and 52,546 for the Greens.

The quota to win an ACT Senate spot was set at 76,423.

Labor’s Senate preference ticket gave preferences to the Greens, with Liberal Gary Humphries in the last, ninth, spot.

The Greens’ Senate preferences gave preferences to the Democrats, followed by Labor, with the Liberals last.

The Liberals also gave preferences to the Democrats, followed by the Greens and then Labor.