The Greens are back to full strength in parliament, but One Nation has lost a senator after three upper house members were sworn-in.
A bitter split between One Nation and a "stunned" newly-installed senator has overshadowed the swearing-in of Australia's three freshest parliamentarians.
Fraser Anning was supposed to be One Nation's replacement for Malcolm Roberts, who was disqualified by the High Court for holding dual citizenship.
He entered the chamber for Monday's swearing-in flanked by crossbench senators Cory Bernardi and David Lyonhjelm while One Nation's Brian Burston and Peter Georgiou sat watching.
An hour later One Nation leader Pauline Hanson said Senator Anning had abandoned the party to sit as an independent.
Senator Hanson blocked four of Senator Anning's staff, who used to work for Mr Roberts, from entering a party room meeting on Monday, accusing them of "disloyalty".
Senator Anning then walked out of the meeting, before seeing on TV he was an independent.
"It seems that without even contacting me, Pauline has unilaterally kicked me out of her party. I have to say I am stunned," he told Guardian Australia.
Senator Anning was joined by Jordon Steele-John and Andrew Bartlett from the Greens in being sworn-in on Monday.
Senator Steele-John, who at 23 in Australia's youngest ever senator, replaced Scott Ludlam who quit parliament after learning he was a dual citizen.
Before his swearing-in, Senator Steele-John promised to be a voice for young people and his state of Western Australia.
He's also looking forward to bringing to parliament a personal perspective on disability issues.
"It's a bit of a mess at the moment," Senator Steele-John said of the saga engulfing parliament at the moment.
"They're dropping like flies."
Senator Bartlett, who was leader of the Australian Democrats in a previous parliament, has replaced former Greens senator Larissa Water who resigned over her dual citizenship with Canada.
"Last time I was here I saw the Liberal and Labor parties join together in 2004 to rush through the changes to the law to bring in entrenched inequality that has caused immense harm and hurt to many people in this nation for the last 13 years," he told reporters.