The Government is being told it must be willing to discuss the age at which people are eligible for New Zealand superannuation.
Treasury on Thursday presented a long term fiscal statement, saying Government debt could balloon.
Treasury suggests several options to try to rein in Government spending, including increasing the age of eligibility for superannuation.
But the Government says it's sticking to its promise not to raise the entitlement age.
However, Auckland University retirement policy and research centre analyst Michael Littlewood says that while New Zealand can afford the current system, it may not be a good use of resources.
He says no government can commit to a superannuation system 20 or 30 years out.
He says many people are choosing to keep working after the age of 65.
Retirement Commissioner Diana Crossan told Morning Report she would like superannuation to stay as stable as it can.
She says a major platform of New Zealand Superannuation is that it's universal, but the country needs to have a free and frank discussion about what it can afford in the future and how it's going to pay for it.