Both major parties expect two new federal seats to go to Labor under a proposal to redraw electoral boundaries, which could effectively wipe out the Turnbull government's majority.
Under the redistribution, Victoria and the ACT will each get an additional lower house representative, while South Australia loses one seat, taking the total number of federal MPs to 151.
A raft of seats will be redrawn and renamed.
Cabinet minister Christopher Pyne agreed with Labor frontbencher Richard Marles that the new electorate of Bean, which will take in southern parts of the ACT, and Fraser in Melbourne's west, are likely to go Labor's way.
But the redrawing of boundaries across 37 existing Victorian electorates is cause for hope for the Liberals, Mr Pyne said.
"The new map for electoral boundaries is as exciting for politicians as an astronomer discovering a new star," he told Sky News on Friday.
"We absolutely love redistributions. We spend days poring over maps, working out what the outcomes are going to be."
Mr Pyne's South Australian seat of Sturt could be abolished when his state's redistribution proposal is released next Friday.
He is confident he will hold his eastern suburban Adelaide seat whatever shape it takes, while Mr Marles was also unfazed by the new electoral map.
As part of the flagged Victorian changes, the division of Corangamite will be renamed Cox, McMillan will change to Monash, Melbourne Ports will become Macnamara and Murray will be Nicholls.
ABC election expert Antony Green said the Liberal-held Dunkley in Melbourne's south-east would become notionally Labor.
Changes to Dunkley and Cox, along with the two new seats would effectively wipe out the government's majority, he said on Twitter.
The ACT will go from two to three federal seats, with the new division proposed to be called Bean, in honour of Australia's official WWI correspondent Charles Bean.
Fenner has been redrawn to cover the territory's north including Gungahlin, Hall and Belconnen, as well as Jervis Bay, while Canberra will take in central parts of the national capital.
Canberra Labor MP Gai Brodtmann announced she will run in the new seat of Bean, subject to pre-selection.
The Greens are eyeing Canberra, which they say will be a contest between them and Labor.
"The seat of Canberra is now one of the greenest in the country. Finally Canberrans have a chance to send someone to parliament who will truly represent them," ACT Greens Co-Convenor Emma Davidson said.
The public has until May 5 to lodge objections.
A half-Senate and full lower house election is due between early August this year and mid-May 2019.