The latest figures from the Australian Electoral Commission show Bridget Archer is 549 votes ahead of Labor's Ross Hart in Bass.
The AEC's figures after counting on Thursday showed that Ms Archer, the former George Town mayor and Liberal candidate, had 33,810 votes or 50.41 per cent of the two-party preferred vote.
Mr Hart had 33,261 votes or 49.59 per cent on a two-party preferred.
Just over 91 per cent of all votes in Bass have been counted.
Election analyst Dr Kevin Bonham said he remained confident that Ms Archer would win the seat which Mr Hart won in 2016.
"It's a foregone conclusion but we have to wait until all the votes are in for it to be officially confirmed," Dr Bonham said.
However, it could be several days before the final vote figures are known.
Postal votes and those cast by voters overseas have still to arrive for counting.
The AEC said that under the Commonwealth Electoral Act it had to wait 13 days for declaration votes to arrive.
In the case of a close seat, this may mean that a result may not be available until after the 13 days have elapsed, a spokeswoman said.
Mr Hart has conceded to Ms Archer.