An economist says Super will become an increasing burden requiring nastier trade-offs, particularly with the current huge hit to the balance sheet.

National Party leader Todd Muller says the party will campaign on raising the eligibility age to 67 by 2040, starting in 2037.

ANZ chief economist Sharon Zollner agrees.

She told Kate Hawkesby fewer people are trying to support more and more retired people over time.

“Our life expectancy has increased but the Super age hasn't, so it's sitting there as a massive liability on our books.”

Jacinda Ardern has pledged Labour will not lift the age of superannuation eligibility.

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