Ballot papers for the leadership of the Australian Labor Party are in the post to ALP members along with blurbs from candidates.
AAP reports ALP members will be sent ballot papers on Tuesday, accompanied by statements from the two candidates Bill Shorten and Anthony Albanese.
"I've devoted my life to serve the Labor party and the nation," Mr Albanese writes in his statement, citing his lengthy political experience and time in both government and opposition.
Mr Shorten on Monday told a gathering at the Australian National University he wanted to lead Labor to victory at the next election.
"I do not need to be the smartest person in the room. I do not need to have the loudest voice or have been in parliament the longest or be the best parliamentary debater," Mr Shorten said.
"I want to be a leader, who through my actions, helps with the Labor team and movement unlock the innate potential that exists within every Australian."
The two contenders will face each other in a debate in Sydney on Tuesday and at another in Melbourne on Friday.
More than 43,000 ALP members across Australia are eligible to vote in the ballot. The final result will be announced on 13 October.