One Nation is targeting a WA seat in Labor heartland. It could be a defining moment for Australian politics | Narelle Miragliotta for the Conversation

The Secret Harbour byelection has the potential for an electoral upset, given the many characteristics conducive to a One Nation win

W here once a byelection for a state seat would have attracted little national attention, the remaking of the Australian political landscape in recent months has given such contests greater significance.

The next such byelection is on 29 August in the Western Australian state seat of Secret Harbour, triggered by the resignation of the Labor government minister Paul Papalia.

Papalia had represented the seat, and its predecessor electorates, since 2007. The area is Labor heartland, with the party’s two-party preferred vote averaging about 60% .

There is, however, the potential for a One Nation electoral upset. The seat has many of the characteristics that analysts identify as conducive to a One Nation victory.

Secret Harbour is an outer metropolitan seat on the southern coastal outskirts of Perth. Like many such electorates, Secret Harbour has high levels of mortgage and rental stress . One Nation polls especially well in seats experiencing high levels of economic anxiety.

The seat’s demographic profile has led William Bowe, a leading election analyst, to suggest its “low ethnic diversity and abundance of trades workers make it promising territory for One Nation”.

A portent of the threat facing Labor is the 28.5% swing recorded against its primary vote at the 2025 state election. Premier Roger Cook recently conceded it was “ absolutely ” possible the party would not retain the seat.

The first is that the Liberals are fielding a candidate. This might not seem unusual, except the major parties are known to engage in “ strategic absenteeism ” at byelections if there is a chance that a third (non-major) party or candidate might defeat the incumbent.

The Liberals’ decision to contest the byelection suggest they believe they are competitive. Also likely is that they are concerned about the optics of being a no-show in the race at a time when One Nation has established a branch in the overlapping federal electorate of Canning, currently held by the Liberal MP Andrew Hastie.

The second is the 16-strong field – nine more than at the 2025 state election. The field includes a regionalist party, several single-issue parties and six independents.

The ideological composition of the field is also noteworthy. Of the 16 contestants, more than half lean right, while four lean left. The composition of the field may signify something about the broader ideological direction of travel of the seat.

Despite the large field, only three parties are the focus of media attention.

It is remarkable that One Nation is even in contention given it gained just 8.4% of the primary vote at the 2025 state election.