Commissioner Jane Wrightson said any change to the age will disadvantage certain groups.
"Any change to the age of eligibility would disproportionately disadvantage manual workers, carers and those they care for, and those with poor health, due to differences in savings, wealth and ability to remain in paid work after the age of 65. Women, Māori, and Pacific Peoples are overrepresented in those groups," Commissioner Jane Wrightson said.
National wanted to raise the retirement age to 67 from 2044, while Labour was sticking with 65.
"General political claims that NZ Super is unaffordable are not supported by independent, publicly accessible analysis," Wrightson said.
"The age of entitlement to NZ Superannuation should remain at 65. Current and projected expenditure does not represent an internationally high proportion of GDP."
According to data from the Organisation for Economic Co-operation and Development (OECD), New Zealand spent 5.1 percent of its GDP on superannuation in 2021, compared to the OECD average of 7.7 percent.
The average OECD retirement age is 64.
"The simplicity of NZ Super's design is internationally envied and New Zealand's expenditure on its pension is relatively low compared to other OECD countries. Current and future recipients say that they want to see its broad eligibility maintained without means-testing," Wrightson said.
The paper gave eight alternatives to a flat hike of the retirement age if "fiscal savings were essential".
Those suggestions included different benefits for those aged 65 and 66, allowing earlier access to a reduced NZ Super amount and requiring some estates to repay NZ Super.
"There needs to be evidence-based discussion about the policy options and the impacts of any change. This paper, along with the Super Summit being held in Wellington next month, aims to contribute to that discussion and to inform the public and policymakers," Wrightson said.
Political support for a stable long-term system was crucial, she said.
"The government should encourage Te Ara Ahunga Ora Retirement Commission to investigate the possibility of a new cross-party accord on the retirement income system to provide stability and certainty for future generations of retirees and to encourage sound decision-making," was one of the recommendations made.
"At the very least, the number of parties who have made a political commitment under the New Zealand Superannuation and Retirement Income Act 2001 could be expanded".
Only National and Labour supported both parts of the Act, while the Greens supported part one.
The paper also called for "a legislated and periodic review (for example every nine years or so) to be undertaken to enable environmental, fiscal, and population changes to be formally and independently assessed by Government."
The Super Summit will be held on 21 March.
