One Nation has secured a fourth seat in South Australia’s lower house, winning Narungga on the Yorke Peninsula.

The seat was so close it required a recount, but has now been won by One Nation candidate Chantelle Thomas by a margin of 58 votes over Liberal rival Tania Stock.

Ms Thomas will join three other One Nation MPs in SA’s House of Assembly.

But the Liberal Party will retain its opposition status after winning five seats at the SA election almost two weeks ago.

Prior to today’s result, Narungga was the only seat that had not been called.

According to her profile on the One Nation website, Ms Thomas is a mother-of-three based in Kadina who hoped to give her community “a strong voice and make it an even better place to live, work and raise a family”.

Her profile said she worked as a photographer and make-up artist and had also worked as a counsellor with Lifeline.

Ms Thomas was declared the elected member for Narungga on Thursday afternoon and thanked her supporters and the electoral staff who worked the recount.

The back of a man counting ballot papers and putting them into different piles under names Thomas, Ellis and Stock

A vote recount for the seat of Narungga concluded on Thursday afternoon. (ABC News)

On Wednesday, Ms Thomas said she decided to join the party to show “clarity, unity and strength”.

“I think everyone in the country is fed up and they want a strong voice to be heard, and that is what I’ll be for them,” she said.

Narunnga was previously held by Liberal-turned-independent Fraser Ellis, who re-contested the seat but only secured around 17 per cent of the primary vote.

A woman with short blonde hair wearing a white jacket

Liberal candidate for Narungga Tania Stock. (Facebook: Tania Stock – Liberal for Narungga)

One Nation’s SA leader Cory Bernardi on Wednesday described the party’s emergence in South Australia as “a seismic shift in politics” and put it down to “a myriad of factors”.

“Number one is that Pauline Hanson has been prosecuting her case for 30-plus years — that’s resonating with a lot of people,” Mr Bernardi said.

“The ‘uni-party’ [are] actually leaving people behind, their rhetoric is now falling empty on many people’s lives, and they realised they’re going backwards and One Nation provides an injection of common sense and hope.”

Mr Bernardi said he would “work cooperatively” across the political divide, and said the first objective the party would pursue was its push to revoke the SA Voice to Parliament.

“We’ve said we want to lower the cost-of-living, reform local government, we want to get rid of net zero and get rid of the Aboriginal Voice to Parliament and all race-based legislation,” he said.

Cory Bernardi on a footpath next to a wall with plant overhanging

One Nation upper house MP Cory Bernardi says he is willing to work with the rival parties. (ABC News)

One Nation MPs held a media conference following their party meeting on Wednesday but the ABC was barred from attending. 

The ABC has been prevented from attending One Nation events since a report about the party’s now-dumped candidate for Adelaide, Aoi Baxter, on election eve.

Hurn: Libs are the opposition

Liberal leader Ashton Hurn said her team would remain the “formal opposition”, as she appointed her new shadow cabinet earlier on Thursday.

“South Australians have actually spoken, they’ve delivered us … the second-most seats in the lower house,” she said.

“We might be a slightly smaller team but we’re not going to be complacent.”

As well as being Opposition Leader, Ms Hurn will take on the shadow portfolios of defence and space, as well as and trade, industry and investment.

Among the other key appointments is Jack Batty as shadow health minister and Heidi Girolamo as shadow education, skills, and training minister.

Ben Hood retains Treasury among several other portfolios and has added energy and mining.

Labor won a massive majority in the March 21 election, with 34 of 47 lower house seats.

Four others are held by independents.