Voters in one of the safest federal Liberal seats in Australia are heading to the polls to choose a successor to former treasurer Joe Hockey.
The North Sydney seat was vacated when Mr Hockey resigned following the ousting of former prime minister Tony Abbott by Malcolm Turnbull.
Mr Hockey's ex-staffer and former acting president of the NSW Liberals Trent Zimmerman is standing for the Liberal party and is widely tipped to win the seat.
The seat has been held by traditional conservative parties since the 1900s barring a six-year stint as an Independent electorate under Ted Mack in the 1990s.
Mr Hockey held North Sydney the 2013 election on a two-party preferred margin of almost 66 per cent.
Twelve candidates, including former NSW MP for the Democrats and Greens candidate Arthur Chesterfield-Evans, are contesting the seat.
The closest contenders are the Greens, which in 2013 racked up a primary vote of just over 15 per cent.
Campaign begins in North Sydney by-election
Labor, which has never won the blue ribbon North Sydney, opted not run a candidate.
The lower north shore electorate, which includes the suburbs of Artarmon, North Sydney, Kirribilli, Lane Cove and Hunters Hill, has the nation's second-highest proportion of high-income families.
A recent poll found most voters supported a global ban on new or expanded coal mines.
CANDIDATES IN NORTH SYDNEY BY-ELECTION
1. Lou Pollard, The Arts Party
2. William Bourke, Sustainable Population Party
3. Sam Kennard, Liberal Democrats
4. Kerry Susanne Bromson, Voluntary Euthanasia Party
5. James Jansson, Future Party
6. Arthur Chesterfield-Evans, The Greens
7. Maryann Bergei, independent
8. Silvana Nero, Christian Democratic Party (Fred Nile Group)
9. Robert James Marks, Palmer United Party
10. Trent Zimmerman, Liberal
11. Stephen Ruff, independent
12. Luke Freeman, Australian Cyclist Party
13. Tim Bohm, Bullet Train For Australia
