In the by-election, former tennis professional John Alexander was re-elected in Bennelong division after stepping down over a dual-nationality row with Labor's Kristina Keneally enjoying a 7.9 per cent swing in support in her favour.
The dual-citizenship crisis forced nine Australian MPs to resign as they were found to hold dual nationality - something politicians are barred from by Australia's constitution.
Following this, Alexander renounced his British citizenship and has now won the re-election even as Deputy Prime Minister Barnaby Joyce did two weeks ago.
The vote had been seen as a test of the credibility of Prime Minister Malcolm Turnbull's ruling Liberal-National coalition. (ANI)