Labour MP Chris Hipkins said National's policy announcement to increase the retirement age from 65 to 67 would hit those workers in lower income jobs.
National Party officials this week pledged to raise the age starting in 2037 if they return to power after next year's election. The party's finance spokesperson, Paul Goldsmith, said the proposal was to ensure the long-term sustainability of superannuation scheme.
But Mr Hipkins told TVNZ1's Breakfast today: "Increasing the age, and you know the Labour Party has flirted with increasing the age previously, the people that that would most affect are the people who are in the lowest income jobs, who are knackered by the time they get to 65 and they don't live very long after that.
"The reality is if we do a good job of saving for retirement through the New Zealand Super Fund then we can actually deliver superannuation at the age of 65, we don't need to increase the age."
He also hit out at National, which would have to be in Government for seven years in a row to implement the policy by 2037.
"They've kicked it out to the future for a problem for another day rather than addressing anything now, that is actually going to make a difference now," he said.
But joining Mr Hipkins on Breakfast, National's Paula Bennett said the 2037 timeline was to gradually introduce the new retirement age.
"It is about sustainability and a change in us as people as to how long we live and the kind of work that we're doing," she said.
She also slammed the other side, saying the Government had talked about tackling the hard issues but then stepped back on the topic.
But Mr Hipkins defended Labour, saying the party had in fact taken the issue to the electorate and lost convincingly both times.