Labor frontbencher Stephen Conroy says the ALP remains hopeful it can still win the Tasmanian seat of Denison.
The seat, one of three still in doubt, is expected to go to independent candidate Andrew Wilkie.
But Senator Conroy thinks that is "a little premature".
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"We think that we're still a real chance in Denison," he told ABC Radio on Monday.
A clearer picture of the outcome might be know later on Monday when the Australian Electoral Commission does a preference count.
Mr Wilkie needs to pick up a large slice of Greens and Liberal preferences to overtake Labor.
If Labor holds Denison and wins the closer-run race in Hasluck (WA) it would have 74 seats in the new parliament, three more than the coalition.
"That puts us very much in play to form a minority government," Senator Conroy said.
However, that number includes newly-elected Nationals MP Tony Crook, who was tipped to take O'Connor from veterans Liberal MP Wilson Tuckey on Saturday.
Mr Crook previously has said he would sit on the crossbench rather than with other Nationals from other states.
On Sunday, the Liberals appeared to have held Boothby (SA) while Labor looked set to win Lindsay (NSW) and Corangamite (Vic).
That left Brisbane (Qld), Hasluck (WA) and Denison (Tas) as the only seats in doubt.
