Zed Seselja has promised to fight to protect public servant jobs if the Coalition wins the federal election.

Zed Seselja has promised to fight to protect public servant jobs if the Coalition wins the federal election. Photo: Jay Cronan

Newly preselected ACT Liberal Senate candidate Zed Seselja has promised to fight to ensure public servants are protected from forced redundancies if the Coalition wins the federal election.

And Mr Seselja has dismissed as a ''disaffected rump'' forces within the Canberra Liberals who have launched action which could lead to his preselection victory against incumbent senator Gary Humphries being overturned.

On Saturday, the former Legislative Assembly opposition leader defeated Senator Humphries by 114 votes to 84 in a ballot of Liberal Party members to pick the No.1 Senate candidate for the election in September.

Mr Seselja - who, like Senator Humphries, is a Catholic - spent part of Sunday door-knocking in Macarthur as part of a St Vincent de Paul Society appeal. He said door-knocking would also be a big part of his campaign for the Senate.

''There will be a lot of grassroots campaigning, spending a lot of time in the outer suburbs of Canberra in particular,'' he said.

Mr Seselja said that if a Coalition government was elected, he would lobby to ensure that Canberra's interests were considered when decisions were being made.

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''If there's an incoming Coalition government, I would be holding them to account to stick to their promise that there will be no forced redundancies, that any downsizing of the public service will come about as a result of natural attrition, so that people can be confidence that they won't be losing their jobs,'' he said.

Hundreds of Liberal Party members were ruled ineligible to vote in the Senate preselection ballot. Some party members have petitioned for a divisional meeting, which could theoretically overturn the result.

Former Canberra Liberal president Gary Kent, who initiated a petition for a meeting of all party members said he was consulting colleagues on whether to press ahead.

''At the moment the overwhelming sentiment is that the preselection was not fair, was not conducted properly and that the meeting should proceed,'' Mr Kent said.

But Mr Seselja did not think a majority of party members - including many supporters of Senator Humphries - would want the preselection reopened. ''I think there is a disaffected rump in the party, and that's about all sorts of things, not just preselections. I think every political party experiences that, but I think the vast majority of Liberals will now want to see the party unite and move forward.''

Senator Humphries declined an interview request on Sunday. Opposition Leader Tony Abbott, who backed Senator Humphries in the preselection, was not available to comment at the weekend.

Now that Mr Seselja he has been preselected for the Senate, Chief Minister Katy Gallagher wants him to quit the Legislative Assembly as soon as possible. Mr Seselja said he was yet to decide when he would resign from his post as MLA for Brindabella.