More volatility looks certain on world markets this week in the wake of the Brexit vote.
The New Zealand market has opened down one percent on Monday morning, following a fall of 2.3 percent on Friday.
But the Commission for Financial Capability says KiwiSaver investors should not panic.
Global markets plunged after a majority of voters in the British referendum voted to leave the European Union.
Markets hate uncertainty and there is a great deal of uncertainty about the result. What will the economic effects be? When exactly will the UK leave the EU? What sort of exit deal will it negotiate with Europe? Will Britain even leave? After all the referendum is not actually binding.
We are in for a period of volatility on world markets. How long it will go on and how bad it will be is anyone's guess.
The Commission for Financial Capability says KiwiSaver is a long-term investment, so you should try to not let short-term volatility put you off.
Nor should you stop contributing or suddenly switch providers.
The Commission says if you have concerns you should talk to your provider to make sure you are in the right fund for your age and risk appetite.
You might want to avoid looking at your KiwiSaver balance for a while.
Of course that is easier said than done. No major market was immune from the sell-off.
The impact on KiwiSaver balances will vary.
Savvy Kiwi founder Binu Paul says 'growth' funds typically have a larger exposure to shares than 'balanced' or 'conservative' funds.
He says 'Growth' funds have around 45 percent invested in international shares, with 'Balanced' funds typically having around 33 percent and 'Conservative' funds around 15 percent.
Mr Paul says if international shares were to go down in value by, say 5 percent, then the impact of the loss on the Growth fund will be 2.25 percent, on the Balanced fund: 1.65 percent and on the Conservative fund: 0.75 percent.
But the managers of many 'Growth' funds do have the option of moving from shares into cash. Some might have reduced their exposure to shares ahead of the Brexit vote.
The currency is another factor. The New Zealand dollar rallied by over six percent against the British pound. But the kiwi slipped against the US dollar.
Those currency moves have an effect on the value of your funds when converted back into New Zealand dollars.
Here is an example:
Last week's gain of 1.95 percent for the FTSE 100 turned into a loss of almost four percent when converted into New Zealand dollars.
Binu Paul says some managers 'hedge' the dollar, which reduces the day to day impact of the currency movements.
"Done correctly, the losses suffered on the underlying asset may be fully (or partly) be compensated for by making gains on the relative movement of the NZ dollar against the currency of the share."
Binu Paul agrees with the Commission for Financial Capability that KiwiSaver investors should take a long-term view.
"If you don't need to withdraw your KiwiSaver savings in the near future, you don't suffer an actual loss. When markets pick up again, those losses may very well turn into gains. Avoid knee-jerk reactions, because if you did sell out now, you will crystalize that loss and deny yourself the opportunity to make up the losses already suffered.
"The key here is to ensure you are in the right Fund that fits your investment time frame and risk appetite."