The average cost of building a home in New Zealand's main centres has risen 21% in the past year, and more price rises are expected, says a construction cost database provider.

Crown-owned QV CostBuilder’s latest pricing update for the end of April, showed more than 60,000 rates were updated, resulting in a 21% increase in the cost to build a standard three-bedroom home since the same time last year.

Since its last update at the end of 2021 the average cost of reinforcing steel had increased 29%, metalwork was up by 18%, external works were up 11%, and piling and excavation costs were up 11%.

The cost of stairs and balustrades increased 17% due to increases in precast concrete and structural steel, it said.

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Substructure increased, and site preparation increased 10%, and framework, windows and exterior doors increased 8%.

On average each trade rate had increased by nearly 7% since the end of 2021, it said.

QV CostBuilder spokesperson Martin Bisset said the rising cost of construction should not come as a surprise.

“But what is surprising is the sheer size of some of these increases, at a time when the construction industry is pretty much at capacity.”

“With inflation and interest rates also rising, and supply chain issues still prevalent, there will be further price increases in the future,” Bisset said.

A shortage of Gib Board in New Zealand has resulted in stock being sold on Trade Me for six times the retail price. There have also been reports of builders stockpiling Gib Board, thefts of supplies from building sites, and fears being raised that the ongoing shortage will send some construction companies under.

The Commerce Commission is undertaking a market study into the building materials industry after raising concerns about a narrow choice of suppliers, some of which may be using “loyalty payments and rebates” to restrict competition for some key products.

QV CostBuilder’s database of costs across six regions – including Auckland, Hamilton, Palmerston North, Wellington, Christchurch and Dunedin – is updated twice per year.

The latest update represented an average 5% increase in the price to build non-residential buildings and a 6% increase in the cost to build residential buildings since the last update.

The average price of building a non-residential building had increased by 14% since April last year.

“It’s important to remember these figures are averages for the six cities covered by CostBuilder and the cost of building will always be dependent on the level of finishes, internal layout, and whether it has a single or double garage,” Bisset said.

QV CostBuilder is a subscription-based building cost platform and subsidiary of state-owned enterprise Quotable Value (QV).

It gives users access data ranging from building costs per square metre, to the indicative costs of more than 10,500 other items, as well as labour rates and more.