Ms O'Byrne polled 6324 primary votes when counting closed last night with Mr Wightman on 4950 and Bass Greens MHA Kim Booth wedged between them with 6088 votes.

Ms O'Byrne polled the second-most primary votes out of all candidates in 2010 but appeared to be punished in last night's poll, some 5000 votes behind her tally on election night four years ago.

It would be Labor's worst state election result in 22 years if it fails to win a second seat.

Ms O'Byrne said she was expecting a big backlash this election.

She said Labor was fighting against longevity in government and a desire in voters for change.

Ms O'Byrne said Labor's 16 years in government would benefit it in opposition.

``We know how a government should be run and we will be able to hold them to a higher standard of accountability,'' she said.

Mr Wightman knows the feeling of a tight race for a fifth seat having snatched victory in 2010 after a close contest between union head Scott McLean and Beaconsfield mine survivor Brant Webb.

The 38-year-old former school teacher was branded during the election campaign as New Labor and said he would love to be part of the party's rebuilding if preferences fell his way.

Mr Wightman said the party had faced enormous challenges going into this election.

He said the successes of this minority government experience and relationship with the Greens had been a tough sell in Bass.

``We've had 16 years in Labor governments in Tasmania, we've had a downturn in the traditional industries - particularly forestry - the global financial crisis, and minority government,'' Mr Wightman said.

``What will be interesting is how this government is viewed in 10 or 15 years.''