Labor claims Bennelong voters have delivered a rebuke of Prime Minister Malcolm Turnbull and his government despite not electing their star candidate, Kristina Keneally.
Ms Keneally, a former NSW premier, conceded defeat in the high-stakes by-election about 8.30pm on Saturday, admitting it had been an intense campaign and thanking volunteers and her family.
There was a swing against Liberal candidate John Alexander of about 5.5 per cent and even thought it wasn't enough to secure victory for Ms Keneally, she claimed it was a success for the Labor movement.
"The people of Bennelong have had their say on Malcolm Turnbull and the Liberals," she told the crowd at Club Ryde.
"The verdict is in, the message is clear: we have had enough of your lousy leadership."
Ms Keneally claimed if the result was replicated in a general election, Labor would claim up to 28 seats.
She said Mr Turnbull had "injected himself" into the campaign by admitting it was a vote on his government.
"There is no doubt that he owns this result. There's no escaping it."
The party had been "energised and electrified" by the result, she added.
Federal opposition leader Bill Shorten agreed the swing against the Mr Alexander, who had to recontest the seat after doubts over his citizenship, was all about the prime minister, not Mr Alexander who has a strong personal vote.
"That entire swing is attributable to Malcolm Turnbull and his rotten policies for this country," Mr Shorten said.
"(Mr Turnbull) said this was a poll on him and his government. Malcolm Turnbull, you are correct. It was."
He said it gave Labor an election-winning swing at the next federal poll.
"Friends, Labor finishes 2017 with a most remarkable wind in its sails, not the least because of the effort of people in this room," he said.
The mood at the Labor party by-election night event turned from optimistic to subdued when it became clear Ms Keneally could not win, with many long faces staring at TV screens as the news sank in.
It regained energy when Ms Keneally and Mr Shorten entered the room and there were chants, cheering and loud applause.
Ms Keneally called the result "extraordinary" and insisted the by-election was "a big fight, but a fight worth having".
