Bill English's plan to only let the Superannuation age rise kick in after the Baby Boomer generation has retired will cost the taxpayer $58 billion.
It means young generations have to pay more to cover superannuation and then wait longer to actually get it.
It's sparking fears of a 'generation war' between Boomers and Gen X and Gen Y.
There is a cosy club of Baby Boomers that makes up much of the National Government that has had huge influence over English's decision.
But now a new Gen X Parliamentary leader is on the scene - Labour's deputy Jacinda Ardern. And she says it's not fair.
"They've basically said anyone from 1972 will be paying for the cost."
Instead of starting now, National's policy won't kick in until 2040 - and that comes at a real cost, according to the Parliamentary library.
If the age changed now, $58 billion dollars would be saved by the taxpayer.
ACT leader David Seymour says the younger generation will be picking up the tab.
"They've been absolutely shafted by a Government that cynically thinks because they won't come out and vote, they can get away with ripping off millennials to the tune of $58 billion over the next 20 years," he said.
Mr Seymour says the super age rise is symbolic of a generational war, where Boomers stand over Gen X and millennials.
He said Boomers like Mr English had access to affordable housing, free education, and will have huge retirement and health bills picked up by the taxpayer.
But Mr English denied younger generations were being ripped off, saying: "I think that is a bit extreme."
The age change will have a direct financial impact on individuals - those who get it at 67 will miss out on $47,000 each the Baby Boomers all get.
Mr English acknowledged it was hard for younger generations.
"That's why we focus on economic policy that supports increases in their incomes, better job opportunities, in a country that's going somewhere."
Mr English's move to raise the age of superannuation is causing plenty of debate in Parliament and more importantly, out in society.
That's the really big question now - how will it go down with voters?