UPDATED 12.35pm: It's a political tit-for-tat over superannuation.

John Key is convinced the opposition wants to reduce how much money superannuates are entitled to.

He adds it makes sense because Labour leader Andrew Little has ruled out every other option.

"If you don't lift the age and you don't basically means test then you have to universally reduce the generosity of New Zealand super - so that must be what he's saying they're going to do."

But Labour leader Andrew Little argues they've never considered that, and never would consider it.

"The truth is, he's scare mongering because he knows that he and his government have been reckless and not putting money aside for the future cost of New Zealand super."

Little says the real plan is to restart contributions to the Super Fund.

"If contributions had stayed roughly at the same level as the average payment made by the Labour government when it was in power, the fund would be at around about $44 billion. It's currentyly at around $27.5 billion.

Earlier this week English said the forecast costs of $30 billion by 2030 were large but ruled out changing anything, saying it was affordable "at the moment".

Labour leader Andrew Little has accused Finance Minister Bill English of "political recklessness" for saying there was no viable political path to changing super and it was for future governments to deal with the costs as they wished.

"That is confirmation of their political recklessness. So they know they've got this big fiscal issue staring them in the face. The political plan is to ignore this and make it everybody else's problem. It is totally reckless. "

Little was unable to set out what Labour would do, saying it was still reviewing its policy.

He said restarting Super Fund payments was a priority, but he has acknowledged he believed Labour's policy of raising the retirement age had hurt it in the last election and said he did not favour it.

He has also ruled out any form of means testing after saying last week Labour would look at the situation of over-65s who worked and got super.