THE Electoral Commission has begun counting crucial "below the line" votes in the race for Tasmania's sixth Senate seat.
While five Senators - Liberals Richard Colbeck and David Bushby, Labor's Carol Brown and Catryna Bilyk, and Green Peter Whish-Wilson - are certain to retain their jobs, the last seat is uncertain.
The below the line votes are those where voters chose to number each candidate from one through to 54, rather than chose to simply vote for a party of their choosing.
As preference flows can vary radically in below the line ballots, Electoral Commission workers have started the laborious process of entering the data into computers that do the final sorting.
While Palmer United Party candidate Jacqui Lambie has been speculated as the winning candidate, Liberal Sally Chandler and even interstate Sex Party candidate Robbie Swan have a chance at winning.
Polling analyst Kevin Bonham said there were a couple of key exclusion points in the count that would decide the contest, chiefly after the election of Senator Whish-Wilson, when a Liberal, Palmer and Liberal Democrat candidate are projected to remain.
"If the Liberals or LDP are last, they are excluded which elects Palmer. But if Palmer is last, they're excluded and elect the Liberals," Dr Bonham said.
However, if the Sex Party, which polled less than 1.5 per cent, was to gain around 700 votes on Labor in the below the line count, they would enjoy a "preference snowball" and win.
Dr Bonham said the election of Mr Swan, a party official from Canberra, would be a "freak event".
"At the moment it still looks most likely to be Palmer, but it's not clear cut, I wouldn't call it by any stretch."
Ms Chandler, who today was projected by the ABC to win the final seat, said she was "patiently playing a waiting game", with final results still a fortnight away.
State operations director David Molnar said 10.5 per cent of Tasmanian voters chose below the line voting, the highest proportion of all states.
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