Polling booths have opened in the Bennelong by-election, with Prime Minister Malcolm Turnbull's one-seat majority in the lower house hanging in the balance.
The final week of the campaign has been filled with stunts and dirty tricks from both sides as polls indicate the major parties are neck and neck.
Mr Turnbull acknowledged it was a "very, very close contest" when he and Liberal candidate John Alexander met with voters at Gladesville Public School.
"Australia's security and prosperity depends on John Alexander being back part of our government, delivering more than 1000 jobs a day," he said on Saturday morning.
Labor candidate Kristina Keneally declared she was feeling "energised" by the campaign before handing out how-to-vote cards at Ryde East Public School.
"There has never been a more important vote in Bennelong," she told reporters.
"Indeed the people of Australia are looking around at Bennelong, looking at this seat and wishing they were having their chance to have a say on this government."
The ALP has sought to redefine the poll as a referendum on Mr Turnbull's leadership.
Meanwhile, the Liberals have continually reminded voters of Ms Keneally's time as NSW premier, when she led Labor to the biggest election defeat in the state's history.
A loss in Bennelong on Saturday would leave the government with 75 seats, meaning Mr Turnbull would no longer have a one-seat majority in the House of Representatives.
A Galaxy poll published in The Daily Telegraph has forecast a close result, with Mr Alexander holding a narrow 51-49 two-party lead over his Labor rival.
