Is 4.1% inflation just the beginning? Middle East tensions are reshaping New Zealand's interest rate outlook

Just as many New Zealand households had seen inflation ease for several consecutive months and were beginning to hope for relief from mortgage pressures, a geopolitical crisis in the distant Middle East has introduced fresh uncertainty.

The latest figures show New Zealand's annual inflation rate rose again to 4.1% in June this year, once more exceeding the Reserve Bank of New Zealand's (RBNZ) target range of 1% to 3%. Meanwhile, international oil prices have recently climbed back above US$100 a barrel. Markets are almost unanimous in expecting the Reserve Bank of New Zealand to raise interest rates again in September, with the official cash rate (OCR) potentially reaching 3.75% over the next year.

From international oil prices to petrol pumps, and from central bank rate decisions to monthly mortgage repayments, this geopolitical crisis thousands of kilometres away is gradually affecting every New Zealand household's finances through a clear chain of economic effects.

A barrel of crude oil reshapes New Zealand's economy again

This resurgence in inflation is not the result of New Zealand's economy suddenly overheating.

Stats NZ figures show the consumers price index (CPI) rose 4.1% in the year to June this year. Petrol prices increased 27.5%, alone accounting for almost a quarter of the overall rise in inflation. More significantly, excluding the effects of petrol and diesel prices, New Zealand's inflation rate over the past year was just 2.9%, back within the central bank's target range.

In other words, this inflation rebound does not mean all goods and services are becoming much more expensive. Rather, rapidly rising international energy prices have pushed overall inflation higher again.

The source of this change lies in the Middle East. Recently, tensions between the United States and Iran have persisted, security risks to Red Sea shipping have escalated, and Iran-backed Houthi forces have attacked Saudi oil tankers. Renewed international concerns over disruption to transport through the Strait of Hormuz have pushed Brent crude back above US$100 a barrel.

For New Zealand, which relies almost entirely on imported fuel, there is very little buffer against such changes.

Westpac chief economist Kelly Eckhold expects 91-octane petrol prices in New Zealand could return to NZ$3.20 to NZ$3.30 a litre in the coming weeks.

If international tensions persist, transport, logistics and business operating costs could rise further, gradually feeding into the prices of more goods and services.

What really worries the central bank

Many people assume this bout of inflation will naturally end once international oil prices fall.

But economists are really concerned about something else.

As operating costs continue to rise, more businesses are preparing to pass those costs on to consumers.

Kiwibank's latest survey shows more than half of businesses currently plan to raise their selling prices over the next three months. A Westpac survey likewise found that the proportion of businesses planning price increases has reached its highest level since 2023.

Reserve Bank of New Zealand chief economist Paul Conway has previously noted that businesses tend to raise prices quickly when costs rise, while lowering them slowly when costs fall.

This means what began as a short-term international energy shock could gradually develop into longer-lasting, more widespread inflationary pressure.

Once businesses believe their costs will keep rising, and consumers believe prices will continue to climb, those expectations themselves encourage further price increases.

This is what worries the central bank most: inflation expectations becoming “entrenched”.

Markets are betting on rate rises again

A few months ago, many market participants still believed New Zealand's interest rates had peaked and that a gradual rate-cutting cycle might follow.

That assessment has now changed markedly.

Financial markets have now almost fully priced in another interest rate rise of 25 basis points in September.

Westpac even forecasts that the OCR could reach 3.75% over the next year.

Meanwhile, the way New Zealand's economic data are released is also changing.

From May next year, Stats NZ will publish monthly consumers price index (CPI) updates for the first time, rather than releasing them only quarterly. The central bank will also increase its annual interest rate decisions from 7 to 8.

This means markets will become more sensitive to inflation changes, and interest rate policy may depend more heavily on real-time data.

For borrowers, monitoring mortgage rates may become an important monthly economic event, rather than something to do just once a quarter.

Mortgage pressure is not over yet

If the central bank continues raising interest rates, households with loans will feel the most immediate impact.

BNZ chief economist Mike Jones expects floating mortgage rates could rise above 6.5% by the end of this year, and potentially exceed 7% in the first half of next year.

Although fixed mortgage rates have already anticipated market expectations, leaving relatively limited room for further increases, the overall trend remains upwards.

For households approaching mortgage renewal, every OCR adjustment could mean higher borrowing costs for the next few years.

However, high interest rates do not necessarily mean house prices will fall sharply again.

BNZ expects national house prices to remain broadly flat overall this year, with growth of around 3% possible in 2027.

This means New Zealand's housing market currently lacks the conditions for rapid short-term growth, while also showing no sign of a sharp decline.

What is really changing is the cost of buying a home, rather than house prices themselves. As mortgage rates climb, buyers' monthly repayments increase significantly even if house prices remain stable. For many households, the decisive factors in whether to buy are now how much the bank is willing to lend and whether they can afford the monthly repayments, rather than the house price alone.

Imported inflation could become the new normal

Looking at several events of recent weeks together reveals a clear chain of economic effects:

Escalating tensions in the Middle East push up international oil prices; higher international oil prices lift fuel prices in New Zealand; fuel prices drive up inflation; renewed inflation forces the central bank to keep raising interest rates; and higher rates further affect the housing market, business investment and household spending.

This is why more economists believe New Zealand is now facing a more typical form of imported inflation, rather than the inflation caused by overheated demand during the pandemic.

The future path of interest rates is no longer determined solely by New Zealand's domestic economy. It is increasingly influenced by international energy markets, global supply chains and geopolitical risks.

For ordinary households, adapting to the future may mean more than coping with higher fuel prices. It may mean adjusting to a more uncertain economic environment that is more vulnerable to international events.

Is your household ready?

4.1% may be just a number, but its message deserves every household's attention: the factors affecting mortgages, fuel prices and living costs may increasingly originate outside New Zealand.

Households will respond differently to simultaneous increases in fuel prices, inflation and mortgage rates. Some are cutting back on unnecessary driving, others are revising their household budgets, and some approaching the end of their mortgage term are considering fixing for longer, splitting their loan across different terms or renegotiating with their bank. But in an uncertain environment, there is no single answer that suits everyone.

Have you already felt the pressure of rising fuel prices and living costs? With mortgage rates potentially rising further, would you fix early, cut spending or wait and see?