"It means fish and chips are a treat - and if you don't want life where fish and chips are a treat then you should start doing something early."
The KiwiSaver scheme was an easy and convenient way for employees to save for later years, Ms Crossan said.
At the end of August more than 2 million New Zealanders had signed up, with more than $12 billion invested.
Individual workers have saved more than $5 billion since the scheme's 2007 introduction. Government contributions total $4.88 billion and employers' contributions more than $2.7 billion.
Ms Crossan said planning for retirement was about weighing up current options with future pay-offs. "There are times in your life when you have to make these decisions about how you manage your money differently."
About 8 per cent of New Zealanders aged over-65 lived in hardship, of which many were renting their homes, she said.
Other figures show about 250,000 people have opted out of KiwiSaver since it was introduced and just over 5000 people have turned 65 and withdrawn funds for retirement.
More than 80,000 others had taken contribution holidays as at the start of September. A contribution holiday can be taken by someone who has been on the scheme for 12 months and wants a break from saving. APNZ
KIWISAVER
Wanganui and Taranaki savers: 76,909 participants
Total savers nationwide: 2,002,840 participants
65-plus withdrawals: Just over 5000
Number of people on a contribution holiday: 86,468 as at September 5
Source: Inland Revenue