United Future leader Peter Dunne says the time is right to make KiwiSaver a compulsory scheme. Nearly 1.4 million people are already contributing.
The Labour Party is also looking at the idea of compulsory superannuation, having rejected it while in Government.
The Prime Minister has ruled out the idea, but Mr Dunne, who is also the Revenue Minister, says there is growing support for making KiwiSaver compulsory.
And he says it could be done by removing the opportunity for people to opt-out of KiwiSaver when they start a new job.