There are 18 federal seats that would change hands with swings of less than 2% at the 2019 federal election.
The Coalition holds eight of those seats - five in Queensland and three in NSW. It holds a further 12 seats by margins of 2-5%.
Labor is defending nine seats with margins of less than 2%.
The 18th seat with a margin of less than 2% is Wentworth, which is held by independent MP Kerryn Phelps.
Of the 20 most marginal Coalition-held seats, eight are in Queensland.
The Coalition-held seats of Capricornia (0.6%), Forde (0.6%), Flynn (1%), Petrie (1.6%) and Dickson (1.7%) would all fall with a swing of less than 2% - which would give Labor majority government, if it holds all its existing seats.
Also potentially vulnerable for the Coalition are Dawson and Bonner (both 3.4%), although Leichhardt (3.9%, held by Warren Entsch) should be safe.
Labor holds Herbert, the nation’s most marginal seat (0.02%), and is looking to defend Longman (0.8%), which it picked up in a by-election last year.
New South Wales
New South Wales holds one-third of the country’s seats, although relatively few are classified as marginal.
The Coalition holds five NSW seats with margins of less than 5%, while Labor is defending three seats with buffers of under 3%.
The South Coast seat of Gilmore (0.7%) is the Coalition’s most marginal NSW seat. Warren Mundine - a former Labor national president - is the Liberal candidate entrusted with retaining the seat. He is fighting off a challenge by the ALP’s Fiona Phillips and another high profile candidate - former NSW Nationals’ Minister Katrina Hodgkinson.
The Coalition is also defending the Central Coast seat of Robertson (1.1%), the far north coast seat of Page (2.3%) and two inner western Sydney seats – Banks (1.4%) and Reid (4.7%).
In Banks, Labor’s Chris Gambian is running for a second time against the Liberals’ David Coleman, who is also Immigration Minister.
In Reid, Craig Laundy has chosen not re-contest for the Liberal Party. It has pinned its hopes on Fiona Martin to retain the seat against a challenge from Labor’s candidate, Sam Crosby.
The Coalition has hopes of wresting three NSW Labor seats.
Labor has selected former NSW Minister Diane Beamer to retain its most marginal NSW seat - Penrith-based Lindsay (1.1%), which was vacated by Emma Husar. It is also aiming to ward off Coalition challenges in adjoining Macquarie (2.2%) and the perennial swinging seat of Eden-Monaro (2.9%).
Victoria will be critical to Labor’s chances of winning the 2019 Federal election. It has been helped by a favourable redistribution which has turned some Coalition-held seats into nominal Labor seats.
For example, Corangamite is held by the Coalition’s Sarah Henderson, who now needs a 0.03% swing to remain the local member. Similarly, Chris Crewther in Dunkley needs a 1% swing to retain the seat for the Coalition.
Labor hopes to win both seats although Corangamite could be a battle. It also hopes to keep its grip on Macnamaa (formerly Melbourne Ports, 1.2%) and Isaacs (3%).
The Coalition is defending three marginal seats in Victoria - Chisholm (2.9%), La Trobe (3.2%) and Casey (4.5%).
Also in the spotlight is Indi, currently held by independent Cathy McGowan by 5.5%. Ms McGowan is retiring at this election, making the seat a much-needed must-win for the Coalition.
At the same time, while public infighting has sapped their effectiveness, the Greens have a strong presence in Melbourne’s trendy and affluent inner east and south-east, the city proper and the gentrifying suburbs to its North. The party aims to at least come second in two current Coalition and three Labour electorates while holding Adam Bandt’s seat of Melbourne (19.1% vs Liberal), their sole presence in the House of Representatives.
Come election night, all South Australian eyes will be on three seats – Boothby, Mayo and Sturt.
The southern Adelaide seat of Boothby has been a long-time Liberal stronghold, but the buffer is down to 2.7%, after being won by Nicolle Flint at the 2016 election.
Centre Alliance’s Rebekha Sharkie holds the once-safe Liberal seat of Mayo. Georgina Downer is hoping to win back the seat once held by her father, former Liberal leader and Foreign Minister Alexander, but needs to achieve a swing of 5%.
In Sturt, former Education Minister Christopher Pyne is stepping down after 26 years in parliament, making the contest for the east Adelaide seat closer than the 5.4% margin suggests.
The election result could be decided by the time polls close in Western Australia – or it could be the state that determines the outcome.
The Coalition is fighting to hold three seats with margins of less than 4% - Hasluck (2.1%), Pearce and Swan (both 3.6%), with the latter being contested for Labor by Hannah Beazley, daughter of former federal Minister Kim Beazley.
Labor’s Anne Aly needs to retain her knife-edge seat of Cowan (0.7%) while Patrick Gorman looks to hold onto Perth (3.3%), a seat he won in a July 2018 by-election.
For a state with only a handful of seats, Tasmania draws plenty of attention every Federal election because so many of its seats are in play.
Historically, its three northern/central seats – Bass, Lyons and Braddon - are extremely volatile. At the 2010 federal election all three were held by Labor, then all lost in 2013 to the Coalition – before all being won back by Labor in 2016.
With such volatility, all three seats have been a focus for both the Coalition and Labor with visits by the Prime Minister and Opposition Leader in the first week of the campaign.
The Coalition requires a swing of 5.4% to win Bass and 3.8% to take Lyons.
Its best hope is Braddon, where a 2.3% would unseat Labor’s Justine Keay (who recontested and won the seat in a 2018 by-election).
Clark (previously Denison) and Franklin in the south of the state are relatively stable with incumbents Andrew Wilkie (Independent) and Julie Collins (Labor) holding healthy majorities and likely to be returned.
The are no seats regarded as marginal in Northern Territory and the Australian Capital Territory.