National is pledging to further increase the default KiwiSaver contribution rate if re-elected at the next election.
The policy is the first firm National policy ahead of the election, which is still around a year away.
At the Budget, the government confirmed an increase to the default contribution from 3 percent to 4 by 2028.
In a speech to National Party members in Upper Hutt, Christopher Luxon said even after those changes, KiwiSaver contributions would still be lower than Australia's equivalent scheme and he wanted to aim higher.
"For Kiwis working in New Zealand, that means smaller KiwiSaver balances and less financial security than friends or family working and saving in Brisbane, Sydney, or Melbourne."
Luxon said if re-elected, National would continue to gradually increase the default contribution rates by 0.5 percent a year until 2032, when both employees and employers would pay in 6 percent each.
As the government is the country's biggest employer, it was estimated that the policy would cost around $90m a year for each 0.5 percent increase.
National said it expected that this would be met within agencies' baselines, although some funding for cost pressures "could become available for certain agencies".
Unlike Australia, the scheme would not be compulsory.
Also at the Budget, the government halved its annual contribution to a maximum of $260.72, and removed it for anyone earning more than $180,000 a year.
The speech was to mark two years of the coalition, with the anniversary coming up on Thursday.
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