The date of the voice to parliament referendum will be announced in Adelaide due to its strategic importance for both the yes and no campaigns, with the potential for South Australia to be the swing state that decides the outcome of the vote.
The prime minister, Anthony Albanese, confirmed on Wednesday he would announce voting day for the voice referendum in Adelaide next week on the 30 August. Referendum day is widely expected to be 14 October.
Guardian Australia analysis has shown both official campaigns have narrowed their advertising to focus more on South Australia, Tasmania and Western Australia, and less on east coast states. The SA deputy premier said she expected her state to be heavily targeted in the campaign.
It is understood the government chose not to announce the date in a larger east coast city, or a location with symbolic importance like Uluru, in part due to South Australia’s importance to the overall outcome.
Campaigners on both sides believe large metropolitan areas in New South Wales and Victoria may mean those states deliver a yes vote, while Queensland’s conservative base could see a no result. Controversy over WA’s Indigenous cultural heritage laws has some tipping that state could also vote no.
The yes campaign needs to win four states and the national result to carry the required “double majority” for constitutional change, meaning voice supporters will need to claim Tasmania and SA.
Yes23 launched its field operation campaign in Adelaide earlier this year. The government’s decision to replicate that for the referendum date announcement was influenced by positive reactions to yes campaign events in SA, according to campaign sources.
Other sources said launching the campaign in Adelaide was to build further momentum in that state with undecided voters, with some in the yes camp believing many people in SA had not engaged with the referendum yet.
The yes campaign is also seeking to make further inroads in Tasmania.
Guardian Australia analysis of Facebook ad spending by prominent pages supporting the yes and no campaigns show that, adjusted for population, both groups are heavily focusing on Tasmania, SA and WA.
Yes23 and Uluru Dialogue largely spent its money evenly across states until June, with a slight emphasis toward WA, but those numbers shifted rapidly as Tasmania, SA and WA became clear focuses for the campaign. By population, Yes23 put its focus on Tasmania, SA and WA in August, with Queensland a little further behind, then Victoria and NSW.
The no campaign started separating its spending out by state far earlier, and skewed its Facebook ad money dramatically toward SA, WA, Queensland and Tasmania. On a population-adjusted basis, the no campaign has paid little attention to NSW and Victoria for the entire campaign.
In June, the no campaign had a heavy focus on WA and SA, but those numbers have since dipped. Instead, Tasmania is now the no campaign’s focus and on a population basis it is easily its major target. Spending per person in Queensland is further back, followed by NSW and Victoria.
At a press conference in Adelaide, the environment minister, Tanya Plibersek, said SA would be “absolutely vital” in the campaign. The deputy premier, Susan Close, said she had confidence SA would back the result, but said it would be a key battleground.
“It is unsurprising that South Australia, I believe more than Tasmania, has been heavily targeted by the no campaigners, particularly on social media,” she said.
“If they can knock out some of the smaller population states it’s cheaper to do because we’re a lower population and they’re able to do damage to the majority of the states test for referendum.”
The yes campaign spokesperson Thomas Mayo said Yes23 was attracting about 1,000 new volunteers a week, and voice supporters were hoping to win all states.
“It’s going to be the biggest campaign that Australia has ever seen … we’re really ready to take this question to the Australian people about recognition,” he said in Sydney.
The treasurer Jim Chalmers, the government’s most senior MP from Queensland, said on Wednesday the campaign would be “especially hard” in his home state.
“It’s still in the balance in Queensland,” he told a press conference.
While many pundits believe results in NSW, Victoria and Queensland may already be locked in, the “double majority” requirement means both sides will be looking to run up their numbers even in states where they may not win, in search of an overall national majority.
In Queensland, where a no vote is tipped, the yes campaign is putting a strong focus on events in Brisbane, which campaign sources noted was one of Australia’s most socially progressive cities with a younger population and a strong groundswell of Greens support.
In Sydney and Melbourne, the no campaign is hosting numerous events aimed at multicultural communities, who they believe may be inclined to oppose the voice.
