Labour candidate Josephine Bartley leads the poll to be the new councillor for Auckland's Maungakiekie-Tamaki ward.
Of the votes cast up by Friday, she took 7073. The other candidate, Josh Beddell, of C&R/Future Auckland, received 5580 votes.
The returning officer for the Auckland Council byelection will release the preliminary result on Monday, following the close of voting at midday today.
Final results will be published on Wednesday - along with those for two other Auckland byelections running on the same timetable - after special votes have been counted.
The ward byelection was needed because of the departure of councillor Denise Lee, a member of the National Party, after she became MP for Maungakiekie.