At that time, Malcolm Turnbull and Tony Abbott were both $1.01 prohibitive favourites, while Home Affairs Minister Peter Dutton was predicted narrowly to retain his Queensland seat of Dickson.
But since November, the number of seats Labor is in front to win has doubled, with the biggest changes in Victoria, Queensland and Western Australia.
Betting markets in Australia and overseas are considered a reliable guide to voting intentions, and often accurately predict results both overall and seat-by-seat.
Late last year, Sportsbet had Labor picking up five Queensland seats, including Capricornia, Forde and Flynn.
It now has Labor leading in another four seats, including inner-city Brisbane (held by the LNP’s Trevor Evans by 6 per cent) and the far north electorate of Leichhardt. Mr Dutton is now $3 compared with Labor’s Ali France, who is at $1.33.
In Victoria, the ALP is favoured at $1.60 to pick up the seat of Flinders, held by Health Minister Greg Hunt, who is at $2.30. Former Liberal MP Julia Banks, now running against Mr Hunt as an independent, is the long shot at $12.
In Ms Banks’ seat of Chisholm, which she won at the 2016 election, Labor’s Jennifer Yang is $1.25 to win, compared with the Liberal Party’s Gladys Liu, who is at $4.
The ALP is also ahead in the Liberal-held seats of La Trobe and Deakin.
In Corangamite, which takes in part of Geelong, sitting Liberal Sarah Henderson – already behind because of a redistribution – is a $5.50 rank outsider, with Labor’s Libby Coker at $1.12.
In Western Australia, Sportsbet had no seats changing hands in November; now it has Labor picking up Hasluck, Swan and Pearce, which is held by Attorney-General Christian Porter. Meanwhile, odds have tightened sharply in Canning and Stirling, where minister Michael Keenan is retiring.
Last week, Mr Morrison spent several days in WA and claimed the state would determine the election’s outcome. But based on the agency’s odds, the election could be over before booths across Western Australia close on polling day.
Other Coalition-held seats where Labor is now favourite include Boothby, Banks, Page and Reid.
Punters also believe Mr Abbott is facing the electoral battle of his life against independent Zali Steggall, who is at $2 to win, compared with the former PM at $1.75.
Overall, Labor is now at $1.16 to win the election, compared with the Coalition’s $4.25.
Election analyst William Bowe said the initial betting markets might have been too generous towards the Coalition.
“The betting markets probably started out a little astray from the polls, and over time there has been a bit of common sense applied to those markets in line with the general polls,” he said.
Mr Bowe said when Scott Morrison replaced Malcolm Turnbull as leader, and opinion polls showed Labor in front by up to 56-44, betting markets did not follow.
He said the Victorian state election had given punters more idea of what voters were thinking.
But he cautioned that the 2016 election had proved that betting markets can get it wrong when it came to individual seats.
At the last election, such seats as Lindsay and Cowan were considered by punters as safe Liberal retains before they were won by the ALP.
Shane is a senior economics correspondent for The Age and The Sydney Morning Herald.