Early voting opens on Wednesday in the Botany by-election for those who cannot make it to a polling station on voting day.
The contest follows the resignation of National Party MP Pansy Wong.
Polling day is 5 March.
At the last general election there were 3182 advance votes and 398 overseas votes for Botany.
Five of the by-election candidates held their first public debate on Tuesday night.
Questions touched on the state of the economy, law and order, affordable housing and asset sales.
Five other candidates were not invited to participate, as organisers said they were unknown independents or from fringe parties.