With National's KiwiSaver changes coming alongside rhetoric aimed at raising the retirement age, Labour has ruled out any changes to superannuation settings.

The National Party plans to make KiwiSaver compulsory for all workers, if re-elected, as part of a suite of changes that would cost more than $1 billion over four years.

Making KiwiSaver compulsory and requiring a higher contribution rate should make New Zealanders better off at retirement - but can they afford to do it?