Why You Need to Stress Test Your Mortgage Now

Sue Tierney

Much like hunkering down for a coming typhoon, stress testing your mortgage can help ensure your finances don't get swept away should interest rates continue to rise.


Whether you are a first home buyer or a seasoned property investor, your capacity to keep up with your repayments is essential to stay on top of your mortgage. However, coming from the less than 2.5% one year fixed rates property owners saw last year, we are now seeing rates climbing up over 5%. If this trend continues, it's entirely possible to see one year fixed rates climb up to 6.0% come next year.


While the rising interest rates can be quite stressful for both aspiring and current property owners, there are certain steps you can take to make sure you stay in control of your mortgage.


What is a Mortgage Stress Test?


One of the key requirements of a successful mortgage application is the borrower's capacity to consistently meet the required monthly payments over the term of the loan. This is more commonly known as the borrower's serviceability.


To be on the safe side, mortgage lenders perform a mortgage stress test by using interest rates that are typically higher than the ones they publicly advertise. While each lender uses their own set of rates when performing a mortgage stress test, all lenders use rates higher than any current mortgage rate forecasts.


For Upcoming Mortgage Applicants


Banks are starting to increase the mortgage rates at which applicants are "stress tested". This is a decision typically made after a bank considers a variety of factors, such as potential housing market economic conditions, the current home loan rate environment, and ongoing interest rate trends. As a point of reference, this rate is as high as 8.15% at one lender.


These higher interest rate requirements can affect a borrower in different ways:


  • A borrower that was pre-approved for $800,000 previously could now have his or her borrowing capacity reduced to $760,000
  • A borrower that had their monthly expenses calculated at $3,000 previously may potentially have that increased to $4,000


While each bank has it's own way of assessing the borrowing capacity of an applicant, it's likely that we will see a decrease in the amount of applicants able to purchase property. This, in turn, can mean a potential decrease in house prices.


For Current Property Owners


When it comes to current property owners, it is essential that you perform a mortgage stress test as early as possible - doubly so if your current fixed rate is expiring soon. With interest rates going the way they are, it's likely that the interest rates you'd be able to fix for in the coming months will be much higher than before. This will likely lead to higher mortgage payments, making budgeting for you and your family much more difficult.


While adjusting to higher mortgage payments can be difficult, there are two key ways you can ease your finances towards a stricter budget:


  • Allocate more of your monthly budget towards potentially higher mortgage repayments by reducing non-essential spending
  • Preemptively save up for a "repayment fund" now, which you can use to top up your mortgage repayments should they increase in the future


Regardless of what method you choose, what's important is that you prepare for a potential increase in your monthly repayments as soon as possible. This way, you and your family won't be caught unawares when you eventually have to fix for a higher interest rate.


Our Team is Here to Help


Increasing interest rates can be a very stressful time for property owners. If you need a helping hand when it comes to sorting out your finances or working with a tighter budget, we would be more than happy to help.

We're here to help you with home loans, personal finance & insurance.

Latest Insights

by Sue Tierney 7 May 2025
Here’s a tip that might come in handy: Get your phone out, open the camera, and video any possession that you might need to claim on your insurance one day. We sincerely hope you never suffer a burglary, fire or flood – but if you do, you’ll be glad you made a record. A few years ago, we made this suggestion to one of our clients. He videoed his stuff – and wouldn’t you know, he was burgled just two days later. This leads to another piece of advice: Make sure you mention this to your insurer, just in case you find yourself in the same position as the person above. You wouldn’t want the insurance company to start wondering if you’d set the whole thing up. Stranger things have happened. A reminder that we don't offer fire and general insurance. We have no skin in this particular game – we simply want to be helpful. However, if you’d like to talk about these types of insurance policies, we can refer you to some trusted advisers. Note that we don’t get paid referral fees or commissions if you arrange insurance with these people: Our contact at Glenn Stone Insurance (GSI) is Lynley Evans, who manages some of our own insurance. Contact her at lynley@gsi.nz You can also use the tool on Frank Risk online. Click on the link here . Alternatively, we’d be happy to refer you to Tower Insurance. We’d need your authorisation to send them your contact details. Note that Tower do pay us a referral fee. Talk to us if you need to look at your life and health cover. If you haven’t reviewed your life, health, trauma, or income protection insurance recently, now may be a good time to do so. This is especially important if your life has changed. Did you get married, start a family, retire, come out of a relationship, take out a mortgage, or experience any other major changes in recent years? We’re not trying to sell you anything – just helping ensure your cover still meets your needs.  Click on the link below to set up a call. There’s no charge.
by Sue Tierney 7 May 2025
The reason is simple. Something you may not think is important could actually matter a lot. It could save (or cost) you thousands of dollars. That’s why we’re always keen to catch up. Talking face-to-face on a video call is an opportunity to find out the things that don’t appear in an email or bank statement. Here’s an example: When a 'cash contribution' from the bank is a bad idea. Banks often use cashback offers or other sweeteners to encourage you to sign on the dotted line. This can be a good deal…or it can be a terrible one. It all depends on your personal circumstances. When we talk to you, we’ll ask questions like these: “Could you reduce your loan in the next few years with a lump sum from KiwiSaver?” “Are you expecting a windfall, such as an inheritance or company shares?” “Are you thinking of selling your house and buying in a cheaper location within the next three years?” Your answers to these questions (and the other questions we ask) will determine the type of loan that’s right for you. The sugar hit of a cash contribution from the bank might turn out to be a false economy, because it could end up locking you into a loan term that doesn’t match your objectives. Here's another example. Refinancing your loan might not be a done deal. Refixing with your bank is usually pretty straightforward. But moving to a new bank – i.e. refinancing your mortgage – may not be. First of all, you will have to go through a complete re-application process. Every lender will need a lot of detail, and their questions could be intrusive. That’s fair enough – they are checking if they want you as a customer. It’s a bigger deal than simply rolling over an existing loan. And you may not even be approved. Then you’re back to square one. Of course, there are times when refinancing is the right option – and we’ll be very happy to do it for you. But first we need to dig into your particular circumstances. So we ask a lot of questions. We're here to help you find the right loan. Your emails and phone calls are always welcome. At Sue Tierney Mortgages, we’re here to give advice whenever you’re thinking about rolling over a loan, taking out finance or changing your insurance. Try us. Click on the link below to set up a call. There’s no charge.
by Sue Tierney 25 March 2025
As Registered Financial Advisers , we’re all about doing the right thing for our clients. A big part of that is making sure you don’t pay a dollar more than absolutely necessary.

Wealth creation is not what you own. It’s what you control.

Deliver Sue’s insights straight to your inbox.