The commission's recommendation to link the age of Super eligibility to lifespan would see New Zealanders receive Super at age 66 by 2037 and 68 by 2056.
Ms Maxwell said the increase would save about $1.5 billion annually.
A similar amount would be saved by another of the 16 recommendations - changing the amount of NZ Super paid by linking it to cost of living increases as well as average after-tax earnings.
Over time that would lead to NZ Super losing ground on average earnings and risk pushing some older New Zealanders into poverty. To address that, a portion of the $1.5 billion savings would be "redistributed to those that will need it the most".
Prime Minister John Key has said he would resign rather than lift the NZ Super age.
Acting Finance Minister Steven Joyce yesterday said Treasury's long-term fiscal projections showed NZ Super was "quite affordable right out to 2060 so we're a long way past 2060 for it to be a big problem".
Labour's policy is to lift the age to 67 over several years to 2020.
Labour leader David Cunliffe said Mr Key and his Government were not telling New Zealanders the truth about the issue.
"I believe he understands very, very well that there's a huge fiscal hole ... if some responsible change is not made.
"The trick is to signal it early so New Zealanders have every opportunity to make adjustments in their personal lives."
The proposals
Retirement Commission recommendations:
* Lift the age of eligibility for NZ Super by linking it to life span so it rises to 66 by 2036, 67 by 2046 and 68 by 2056 as life expectancy increases.
* Link NZ Super payments to general inflation as well as average earnings.
* Apply some of the $1.5 billion annual savings from the change in indexation to maintain living standards for less well off older New Zealanders.
* Keep the age of access to KiwiSaver at 65 while the NZ Super age rises.
* Auto enrol all New Zealanders in KiwiSaver who are not currently in the scheme while preserving the right to opt out later.
* Tax returns on savings only on the proportion above the rate of inflation.
* Investigate means of providing greater "age friendly'' housing and workplaces.
* Deduct overseas state pension entitlements from NZ Super.