What happens if I need the money before I'm allowed to have it?

A lock, or a toll

Before the detail, the shape of it, because the two designs ask you completely different questions.

A locked doorNew Zealand and Australia. You cannot take the money unless you fit a published ground, and someone else decides whether you do.A toll gateThe United States. You can take it whenever you like, and pay income tax plus an extra 10 per cent unless an exception applies.

In New Zealand and Australia the question is whether you qualify, and the answer is given by a supervisor or a fund rather than by you. In the United States the question is whether it is worth the cost, and the answer is yours.

New Zealand: the list is in the Act

KiwiSaver's grounds sit in Schedule 1 of the KiwiSaver Act 2006, which means they are not a provider's policy and do not vary from scheme to scheme.

Significant financial hardship. Clause 11 defines it as significant financial difficulties arising from any of:

• "a member's inability to meet minimum living expenses"
• "a member's inability to meet mortgage repayments on his or her principal family residence resulting in the mortgagee seeking to enforce the mortgage on the residence"
• "the cost of modifying a residence to meet special needs arising from a disability of a member or a member's dependant"
• "the cost of medical treatment for an illness or injury of a member or a member's dependant"
• "the cost of palliative care for a member or a member's dependant"
• "the cost of a funeral for a member's dependant"
• "the member suffering from a serious illness"

Two limits come with it. The supervisor "must be reasonably satisfied that reasonable alternative sources of funding have been explored and have been exhausted", and may "direct that the amount withdrawn be limited to a specified amount" that is what is actually required to relieve the hardship. And the amount available is the accumulation less the Crown contribution, so the government's own top-ups stay where they are.

Serious illness is a separate and more generous ground. Under clause 12 the whole accumulation can come out, the Crown contribution included. Serious illness has a strict statutory meaning: an injury, illness or disability "that results in the member being totally and permanently unable to engage in work for which he or she is suited by reason of experience, education, or training", or "that poses a serious and imminent risk of death".

Note the words "totally and permanently". This is not a ground for being unwell, or for being unable to do the job you used to do.

Australia: two doors, and they work differently

Compassionate grounds are decided by the Australian Taxation Office rather than by your fund, and the eligible expenses are a published list of six:

• medical treatment
• medical transport
• modifying your home or vehicle to accommodate a severe disability
• palliative care
• death, funeral or burial expenses for a dependant
• preventing foreclosure or a forced sale of your home

Read that against New Zealand's list. Two countries wrote these rules separately and arrived at very nearly the same seven or eight situations, which tells you something about which emergencies people actually face.

Severe financial hardship is decided by your fund, not the ATO, and it turns on your age relative to your preservation age.

Under preservation age, you need both of: "You have received eligible government income support payments for a continuous period of 26 weeks", and "You are not able to meet reasonable and immediate family living expenses." What you can take is capped: "The minimum amount that can be withdrawn is $1,000 and the maximum is $10,000", with one withdrawal in any twelve month period, and a smaller balance can be taken in full.

At preservation age plus 39 weeks, the test changes and the cap disappears. You need 39 cumulative weeks of eligible income support after reaching preservation age, and to have not been gainfully employed when you apply. Then "there are no restrictions on how much you can withdraw".

There are also separate routes for a terminal medical condition and under the First Home Super Saver scheme, each with its own rules.

The United States: no lock, a price

American retirement accounts are not preserved in the same way. You can take money out of a 401(k) or IRA before 59½. What happens is a tax consequence rather than a refusal: "Most retirement plan distributions are subject to income tax and may be subject to an additional 10% tax."

Ten per cent on top of ordinary income tax is a real cost, and it is not the whole cost, because the money also stops compounding. But it is a price rather than a gate, and nobody has to be satisfied of anything before you pay it.

And the exceptions are wide. The additional tax does not apply for death or total and permanent disability, unreimbursed medical expenses above 7.5 per cent of adjusted gross income, a series of substantially equal payments, separation from service at 55 or later (50 for public safety employees), health insurance premiums while unemployed, a qualified birth or adoption up to $5,000, a domestic relations order, an IRS levy, qualified higher education expenses or a first home up to $10,000 from an IRA, and certain military reservist and disaster recovery distributions.

Several of those overlap almost exactly with the New Zealand and Australian grounds. The difference is what happens when you do not fit one: in the United States you pay 10 per cent and take the money anyway, and in the other two you do not get the money.

What to take from the comparison

If your savings are in New Zealand or Australia, the work is in the application. Someone else has to be satisfied, there is evidence to produce, and the amount released may be less than you asked for.

If your savings are in the United States, the work is in the arithmetic. The money is available, and the question is what taking it costs you now and later.

If your savings are split across them, both apply to different parts of the same problem, and the order you draw on things in is worth thinking about before the emergency rather than during it.

What this guide does not tell you

It does not cover reaching the ordinary access age, which needs no grounds at all.

It does not cover the other early withdrawal routes each country has for reasons that are not emergencies: buying a first home, permanent emigration, or a life-shortening congenital condition in New Zealand.

It does not tell you whether a particular application would succeed, because that is a decision for a supervisor, a fund or an agency on evidence about you.

And it does not cover the tax consequences in a second country for someone who takes money out of an account held in the first.