The ACT Justice department has been asked to review Zed Seselja's recent senate preselection.

Zed Seselja (front) and Gary Humphries scramble to gain last-minute support. Photo: Colleen Petch

Both sides in the Canberra Liberals preselection battle are frantically lobbying party members for their vote at Wednesday night's crucial party meeting.

Canberra Liberals were being lobbied by telephone and in person on Wednesday afternoon, as the two camps used the final hours before the 7pm gathering to make their case to members.

Up to 400 party members will meet at the Rex Hotel in Canberra's inner north to vote on a motion to overturn last month's preselection results for the Senate and the lower house seats of Fraser and Canberra.

The bitter dispute has divided the party since former ACT Opposition Leader Zed Seselja challenged incumbent Senator Gary Humphries, with many party members claiming they were unfairly denied the right to vote.

Former division president Gary Kent, who has led the push by disaffected party members, said both sides had been working the phones on Wednesday to get their supporters to the meeting.

Mr Kent said a number of members would speak for and against the motion on Wednesday, before putting it to a vote.

"I hope the members will vote for a fair preselection," he said.

"I think there's a good possibility it will be overturned.

"It's ultimately up to the members after hearing their arguments."

ACT Opposition Leader Jeremy Hanson, who has backed Mr Seselja for the number one Senate nomination, said the divisional council was "a matter for the members" but he hoped Wednesday's meeting would lay the feud to rest.

"What I do want to see is this now put behind us so we can get on with the very important matter of taking on the federal government," he said.

"I hope people act with the interests of the party at heart – I'm confident that will be the case."

Earlier on Wednesday, federal Opposition Leader Tony Abbott pledged his support for Senator Humphries in the event of a second preselection.

Mr Abbott said he had been "very clear in supporting Gary Humphries".

"Gary Humphries is a member of my front bench, he's done an excellent job, he's a very experienced, very well respected politician," he said.

"He was a well-respected chief minister of the ACT.

"In the end, I accept that these are matters for the lay party and I will respect the decision of the lay party.

"But as one of my front benchers, Gary Humphries obviously has my full and total support."