National's Penny Simmonds admits she's feeling the pressure to retain the seat for her party as preliminary results show a very close contest with Labour's Liz Craig.

“It’s been a bit nerve wracking... the votes feel like they been taking such a long time to come in Invercargill,” she said.

The race has been almost neck and neck all night. After the buzz of a brief lead, the tables have turned again and at the time of writing 70.2% of the votes had been counted and Liz Craig was leading by 396 votes.

Ms Simmonds said fingers and toes were all crossed for a win to hold the seat for National.

Liz Craig said it had been a really positive campaign, a highlight of which had been getting out and talking to people and getting to know the community.

She agreed it was too early to call an Invercargill result but said she thought people had been really appreciative of Labour post COVID-19.

That is certainly reflected in the party vote in the Invercargill electorate, which currently stands at 48.9% for Labour and 29.4% for National.

Meanwhile, National's Joseph Mooney has established a 4520-vote lead over fellow first-time candidate Jon Mitchell (Labour) in the redefined Southland electorate, with 85.2% of the vote now counted.

National has also closed the gap in the party vote in the electorate but Labour still leads on 38.5% to National's 36.9%.