Government officials are reviewing KiwiSaver's default provider arrangements because the terms for those providers are set to expire in 2014, five years after the scheme was introduced.
There are five government-appointed default providers which automatically invest members' funds into the scheme's conservative investment fund option, unless people choose a different scheme.
In the past year 17,500 people joined KiwiSaver on a monthly basis, taking the total membership to more than two million people.
And at March this year almost a quarter of KiwiSaver members were still in default schemes.
But the Government says those defaults were designed as a short-term measure.
It says that when KiwiSaver was launched, then-Labour Government wanted to promote confidence in the scheme by reducing the likelihood of capital loss.
As a result the default position's investment approach has been conservative, rather than a longer-term focus which could maximise retirement income.
And it was assumed members would move into more growth-oriented schemes tailored to a an investor's life stage and likely risk profile.
The Government says now that KiwiSaver has become the central pillar in the retirement savings of many New Zealanders it is a good time to look at how the default provider arrangements can be improved.
The Government is also looking at the impact of fees on returns to investors, including introducing a fixed-fee rather than a percentage-based fee.
Submissions close on Christmas Eve.