Tom Venning, whose uncle Ivan Venning was a long-time Schubert MP, convincingly won a ballot of more than 400 Liberal Party members at the Port Augusta community sports hub on Sunday, earning the right to contest South Australia’s largest seat at the next federal election.

The 30-year-old candidate saw off a preselection field that included well-known Kimba Mayor Dean Johnson and former United Australia Party candidate Suzanne Waters, who had the backing of right-wing senator Alex Antic.

Venning won 196 votes to Waters’s 78 and Johnson’s 67. The other two candidates, Whyalla police sergeant Matt Sampson and former Family First staffer Rikki Lambert, won 34 and 28 votes respectively.

Grey, which covers more than 92 per cent of South Australia, was arguably the Liberal Party’s most prized federal preselection this year after sitting MP Rowan Ramsey announced in March he would be retiring from politics at the next election.

The seat of Grey is the third largest electorate in Australia. Map: AEC

The Liberal Party has held the seat since 1993 and Ramsey has been the incumbent since 2007. He currently holds the seat on a 10.1 per cent margin over Labor, meaning Venning is likely to be a federal MP after the next election.

Right faction figures have long described – and criticised – Venning as one of the more moderate candidates in the preselection field, although he is officially unaligned.

His preselection campaign is understood to have focused on cost of living, primary production, road funding and regional healthcare and childcare.

The Venning name has a long history in the Liberal Party, with Tom’s uncle Ivan representing the state seat of Schubert from 1990 to 2014. Ivan’s father Howard was also once a Liberal and Country League MP.

Earlier this year, he returned to work on his family’s farm, Barunga Grains, near Bute on the northern Yorke Peninsula. His Dad, Max, was once the chair of grain company AusBulk.

Previously, Venning worked for NAB as an associate director of mergers and acquisitions and as a consultant with Accenture, Deloitte and Capgemini.

One Right-aligned source said there was “no doubt that he lobbied the Liberal members comprehensively throughout the long preselection”.

“He was full-time campaigning as opposed to the others who still had their work obligations at home,” the source said.

“The real work starts for him now as he must convince people from right across this massive electorate that he can actually do the job as the MP.”

State Opposition leader Vincent Tarzia is understood to have addressed the preselection college in Port Augusta and urged them to unite behind the successful candidate.

State Opposition leader Vincent Tarzia, Liberal Party candidate for Grey Tom Venning and federal Liberal senator Simon Birmingham after Sunday’s preselection ballot. Photo: Vincent Tarzia MP/Facebook

The Labor Party expects to preselect its candidate for Grey between late October and the end of November.

But Venning’s biggest threat to becoming a federal MP could come from a Climate 200-backed independent.

Self-described community group Independent for Grey began searching for a candidate in July and has indicated it is willing to accept funds from Climate 200, the fundraising group which bankrolled the Teal independent wave at the 2022 federal election.

“We have had interest,” said Andrea Broadfoot, a former Nick Xenophon team candidate for Grey who is now coordinating the Independent for Grey effort.

“We’re now working through continuing our community listening process to align the electorate’s priorities with the candidates skills and acumen.”

Broadfoot, who nearly defeated Ramsey in 2016 with 48 per cent of the two-candidate preferred vote, said Independent for Grey’s selection process would be “fair, open and transparent”.

“We’re in the process of running community listening events to look at what the electorate would like represented in parliament,” she said.

“That process is happening and then we’re looking to identify a suitable candidate around November.”

Venning’s preselection in Grey all but wraps up the Liberal Party’s federal preselection season, with only the safe Labor seats of Kingston and Spence remaining.

In May, Right-aligned Nicolle Flint was confirmed as the party’s candidate for Boothby – her former electorate which looms as a critical marginal seat at the next election – along with Amy Grantham in Adelaide and Irena Zagladov in Makin.

Right-winger Zane Basic was then confirmed in August as the party’s candidate for the former blue-ribbon seat of Mayo, which has been held by independent MP Rebekha Sharkie since 2016.

Defence industry engineer Christopher Lehmann is also running for the Liberal Party in Hindmarsh, held by federal Health Minister Mark Butler.