Independent Kerryn Phelps has been formally declared the winner of the Wentworth by-election, joining the Lower House crossbench and ending the Morrison government's one-seat majority.
The result has been expected since mid-October, when the largest official by-election swing against a government in Australian political history appeared to doom the Liberals' chances of retaining Malcolm Turnbull's former seat.
Wentworth has been held by the conservative side of politics since the seat was created.
Now, the local doctor and Sydney City councillor says she wants to bring politics back to the "sensible centre" and force the Morrison government into action in key policy areas like climate change and offshore detention of asylum seekers.
Dr Phelps has repeatedly said she does not want to bring down the government - ruling out supporting no-confidence motions unless there were "exceptional" circumstances.
But the newly minted independent MP will use her voting power as part of the crossbench to block or modify bills she fundamentally disagrees with.
"What I would be seeking to do is to modify any legislation or government policies that sought to drag Australia further to the right," she told ABC Radio on Monday morning.
The final result, after preferences, saw Kerryn Phelps defeat the Liberal candidate Dave Sharma 38,989 votes to 37,138.
Dr Phelps claimed victory on the night of the by-election on October 20 when she achieved an unprecedented swing of more than 20 per cent against the Liberal Party in the eastern Sydney seat. But that changed the day after as the margin between the two narrowed to less than 900 votes while postal votes were still being counted.
Since then, electoral officials have been processing and roll checking postal votes, pre-poll declaration votes and provisional votes.
Dr Phelps plans to stay on the Sydney City Council once she takes up her seat in federal parliament.
But she won't say whether she will reveal the legal advice she relied on to ensure she is eligible to sit in Wentworth under section 44 of the constitution.
The section of the constitution bans people from sitting in parliament if they earn money from taxpayer funds.
Dr Phelps' position as a university professor, and her role as a GP receiving Medicare payments, could mean she is potentially breaching the rules.
But the independent has previously told reporters she's satisfied she's not breaching section 44.
