But it’s not just the slim margin that makes the electorate interesting.

Welsh will also be watching Melbourne seats like Menzies and Deakin, where a similar demographic may result in votes shifting from Liberal to Labor.

“Regional NSW also looks like it could be a problem for Labor, including seats such as Hunter and down the coast to Gilmore,” Welsh said.

What is a marginal seat?

But experts generally identify specific key seats using analysis of polling and other factors.

Key seats to watch on election night

Redbridge has pinpointed 20 significant seats that could lead to intriguing face-offs between Labor and the Coalition, alongside other electorates where independent candidates and those from the Greens may emerge as strong competitors.

Key contests between Labor and the Coalition that experts will be watching on election night. Source: SBS News

Other seats where independents or Greens could be elected include:

• Coalition facing off against independents in Kooyong, Goldstein, Curtin, Mackellar, Calare, Cowper, Monash and Wannon.
• Labor is facing an independent in Fowler.
• Labor is facing a Greens candidate in Wills.
• Three-cornered contest between Labor, Coalition and the Greens in Brisbane, Ryan and Macnamara.