“Labor was the underdog in both Braddon and Longman but Labor never gives up,” Mr Shorten told reporters.
The Labor leader said a defeat would be a “message that we didn’t get enough votes”, hosing down speculation about threats to his leadership if Labor loses a seat or two.
“Let’s not give up yet,” he said.
Mr Shorten stopped for a customary election-day sausage, adding a quip at the prime minister’s expense.
“If I was Malcolm Turnbull I'd ask for a knife and fork, wouldn’t I.”
The prime minister is stressing how rare it is for a seat to flip back into government hands in a by-election. It has not happened in Australia since 1920.
“Labor should be miles ahead. These are by-elections. By-elections invariably swing against the government of the day,” Mr Turnbull said.
"Don't let Bill Shorten get a win and be able to see justification for his plan for higher taxes."
Hecklers take aim
Politicians faced off with the inevitable hecklers as they handed out how-to-vote cards with local candidates.
“Why are you giving all the money to the banks?” one asked Mr Turnbull, before challenging him on funding for hospitals.
Mr Turnbull said hospital funding had increased in the two budgets under his leadership and said the accusation was based on “Labor lies”.
“Thank you for acknowledging I was speaking the truth,” he said as the argument drew to a close.
Meanwhile in Longman, Liberal candidate Trevor Ruthenberg was heckled over his recent mix-up of military medals.
“Are you wearing your medal today?” someone shouted.
Home Affairs minister Peter Dutton, who accompanied Mr Ruthenberg to the polling station, said the hecklers were “union thugs”.
“Such good ambassadors for the Labor party,” Mr Dutton said.
Meanwhile in Mayo and WA
The two WA seats, Perth and Fremantle, will be safe holds for Labor as the Coalition is not fielding candidates, despite Labor only winning Perth by two per cent at the 2016 election.
Labor campaign posters declared the government "missing".
The South Australian seat of Mayo will be a closer contest.
The seat is the only one not held by a Labor incumbent - instead, Centre Alliance's Rebekha Sharkie is attempting to hold against Liberal candidate Georgina Downer.
Ms Sharkie said she was "nervous" but "hopeful", while Ms Downer pledged to contest the seat again at the federal election whatever the result this weekend.
Vote counting will begin on Saturday evening and rough results are expected the same night, but some of the closest seats might be too close to call until Sunday.
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