The change would open preselection of candidates to as many as 1500 party members in Canberra, instead of the 500 eligible at the moment.

The move comes from the party's left and will be voted on at the party's July 29 conference, where the left faction has the majority of votes.

At the moment, party members have to belong for at least 12 months and attend a certain number of meetings a year - up to three meetings, depending on how long they have belonged.

If the party abandons the meeting rule, people will only have to belong for 12 months and be enrolled in the right electorate to vote for candidates.

Supporters of the meeting rule say it is designed to avoid branchstacking, and to ensure that people have involvement and interest in the party, its members and its processes.

They question the motivation for removing the rule, and suggest it might open the way to a challenge to one of the sitting federal members, Gai Brodtmann, from the right, or Andrew Leigh, who is unaligned.

But party secretary Matt Byrne said it was about "democratising the party" and helping it become more family friendly because not everyone could attend meetings.

"The party has to respond to the fact that people's lives and the way people respond to politics is different to the way it was in the 20th century," he said. "We currently have a system that rewards people who can take time out of their lives to participate internal processes."

Mr Byrne said members would still have to belong, be correctly enrolled in the electorate and be financial, "so it's not a free for all". The move would bring Canberra into line with all other states except Tasmania and NSW.

"Members represent the party in all walks of life. They already get a vote for the federal leader, but because they can't meet an often complicated set of requirements they miss out on voting in important votes like preselection," he said.

"We shouldn't disenfranchise people because they're not able to make a meeting."

The party is alive with rumours of a challenge, and factions are organising ahead of the possibility of a third seat up for grabs in Canberra. Members of the right believe the left want Ms Brodtmann's seat in the south, and are keen to open up the number of pre-selectors to break the power the right has in the southern suburbs.

But party members also concede that it is more difficult for either faction to control the votes if the wider membership is involved. If a hopeful candidate did persuade a group of supporters to join the party and vote, they would still be facing the need to convince a much larger number of long-term party members to support them.