Nominations for the party's preselection process closed at midday on Wednesday, with the credentials committee set to meet later that day to confirm the eligibility of candidates.

Shadow assistant treasurer Andrew Leigh won't face a challenge for the seat of Fenner, but the contests in the two other lower house seats involve at least four candidates in each.

After the shock resignation of Gai Brodtmann on Monday, four candidates have rushed to put their hands up for the seat of Bean, where Ms Brodtmann had previously intended on seeking preselection.

Senator David Smith gained the endorsement of the party's right faction on Tuesday night, at a marathon meeting with two hours of debate. While Senator Smith wasn't officially challenged for the faction's endorsement, there were reports two or three women were considering nominating, but were discouraged from doing so by members of the powerful Shop, Distributive and Allied Employees Association.

He will face a challenge by the left's Louise Crossman, unaligned Taimus Werner-Gibbings and former campaign manager for Gai Brodtmann, Gail Morgan.

Ms Crossman, an ACT public servant and former president of the ACT Labor branch, said she was "experienced but I'm not an insider" and although she doesn't live in the electorate, already had made plans to move southside at the end of this year.

After it was confirmed the left would challenge Senator Smith in Bean, it was decided late on Tuesday that the right faction would be represented in the Senate race by chief of staff to Gai Brodtmann, Victoria Roberston.

There were no late surprises when it came to nominations for the seat of Canberra, with all previously announced candidates officially putting themselves forward. St Vincent de Paul boss John Falzon will represent the left against former staffer Alicia Payne and lobbyist Simon Banks. The right had previously decided not to endorse one of either staffer Jacob Ingram and greyhound lobbyist Kel Watt for the seat, but that ballot is expected Wednesday night.

It's unclear what would happen if the party's members voted for three men in the lower house seats, leaving it in contravention of the party's affirmative action rules designed to increase the number of women in Parliament. It could require the preselection process to be re-opened and another ballot to take place.

The three lower house seats are generally considered to be safe Labor seats, with the races for Canberra and Bean the first in the territory without incumbent members since 2010, adding to the factional jockeying.

Meanwhile, the ACT Greens are soon to announce their candidates for the next federal election, with the party set to make a concerted push to try and take the seat of Canberra.

The Canberra Liberals have already preselected Senator Zed Seselja to represent the party's upper house bid, with preselection for the lower house expected to take place next month.