Refugee advocates will deliver Scott Morrison and Bill Shorten a petition to remove the remaining asylum seeker children from Nauru.
As of Sunday, there were 12 refugee children remaining on the Pacific island.
Since the Kids off Nauru campaign was launched in August, almost 170,000 people have signed the petition, and it will be handed to the prime minister and the Labor leader in Canberra on Tuesday.
Advocates from World Vision, GetUp, Asylum Seeker Resource Centre and the Refugee Council of Australia will be supported by three politicians at Parliament House.
Along with some former refugees, who now live in Australia, the advocates will be flanked by Greens Senator Nick McKim and independent MPs Kerryn Phelps and Andrew Wilkie.
Dr Phelps, who was officially sworn in as a member of parliament on Monday, has made getting children off Nauru a priority since winning the Wentworth by-election in October.
Australian Associated Press