KiwiSavers are being urged not to panic, amid reports the nation's Super Fund could lose up to half its value.
The Super Fund said on Thursday if there was a repeat of the global financial crisis which rocked the world in 2008-9, $20 billion could be wiped off its books - a loss of 52.6 percent.
The same day the NZX lost 3.6 percent, and has dropped another 1 percent on Friday morning, following losses in the US and Asian markets.
Retirement Commissioner Diane Maxwell says those with money in KiwiSaver shouldn't "mess" with their accounts, even if it looks like they're losing money.
"KiwiSaver members may see a drop in the balances over the next week as the effects of the share market fall ripple through to returns, but they shouldn't panic," she said.
"Like all long-term investments, your KiwiSaver balance will go up and down as the market fluctuates, but hang in there and you will gain in the long run."
She says every time markets dip, the Commission for Financial Capability - which Ms Maxwell heads - hears from worried savers.
"The best thing to do is sit tight, ride out the low patches and know that when the market rises again, so will your balance.
"We all get excited by our KiwiSaver balance when we see it in our banking apps; the downside is that we may be watching it too closely. KiwiSaver is a long game that will have bumpy patches, but will pay off in the end and make a huge difference to your retirement."
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KiwiSaver funds invested in conservative portfolios show less volatility, but won't make as much in the long-term. They're generally recommended for people close to retirement who don't want to risk huge losses.
Growth funds will fluctuate more, but in the long-term are the best bet. They suit people who won't be cashing in anytime soon.
The Super Fund is the Government's investment portfolio intended to pre-fund New Zealand's growing superannuation commitments in the coming decades.