Wellington metro amalgamation to cost $270m, deliver three times the savings over 25 years

Thursday, 23 July 2026

Setting up a metro authority encompassing Wellington, Porirua and the Hutt Valley could cost its residents $269 million – but projected savings will only come over the next 25 years.

A new financial analysis estimates efficiencies of $930m over 25 years, or a net $159.80 a year for each property.

The mayoral forum of the nine Wellington and Wairarapa leaders commissioned advisory firm MartinJenkins for the indicative analysis, before their respective local councils decide the details of the final plan that must be sent to the Government by its August 9 deadline.

The firm already briefed Wellington and Wairarapa councillors earlier this week, with Wellington City’s councillors discussing the details at open briefings on Thursday.

Kāpiti mayor Janet Holborow, whose council is about to decide whether to ask for a standalone Kāpiti Coast unitary authority in the final proposal, said there was limited financial benefit across the board.

Modelling on different amalgamation combinations, the MartinJenkins report concluded all of them “had the potential” to be financially beneficial, churning out $3900 to $4500 of net savings for each property over 25 years.

Larger-scale amalgamation transformed to greater efficiencies, assuming the bigger economies of scale converted to higher savings and greater buyer power.

An all-encompassing mega authority of Wellington, Wairarapa and Horowhenua would take $273m to set up. That could generate $1.2 billion of efficiencies over 25 years, or $156.44 of annual net savings per property.

It would need $281m to found a combined authority for Wellington metro areas, Kāpiti and Horowhenua. In return there could be $1.1b of savings across 25 years, or $155.60 annual net benefit each local property.

On their own, an amalgamated Horowhenua and Kāpiti would cost $58 million to establish. For the next quarter of a century, MartinJenkins estimated $240m of savings, or a net $157.2 a year for each property.

Wairarapa’s three councils, whose regional services are effectively subsidised by Wellington ratepayers, would need to spend $42mn to combine into a single authority, to save $170m over the coming 25 years, or a net $180.80 per property a year.

But the report said losing the subsidies from Wellington could “outweigh any amalgamation-related savings” and the new Wairarapa authority had a $8m budget hole to fill, echoing another report by Morrison Low that ratepayers could face larger bills.

“It is plausible that rates revenue would need to increase to balance the budget,” the report said. “A future Wairarapa authority would need to weigh its options carefully, including considering changes to levels of service, finding greater savings, and/or increasing revenue.

“Given the size of the funding gap, an increase in rates could outweigh any amalgamation-related savings” the report said.

Wellington mayor Andrew Little said it was “hard to know” whether MartinJenkins’ numbers would quell amalgamation sceptics and the ball was now in every council’s court.

“I think at the very least there does need to be some coming together of some councils, there does need to be some amalgamation,” he said.

“What that looks like, each council has to debate that.”

Holborow said Kāpiti would look more carefully about where the benefits might be on amalgamating with Horowhenua. “What we do know is our financials look pretty good as a standalone unitary authority, and we can afford to deliver regional services locally.”

Upper Hutt mayor Peri Zee said the costs were significant and the benefits were “unlikely to be realised on any reasonable term”.

Porirua mayor Anita Baker said in the long run, amalgamation’s rewards were bigger than the numerical efficiencies because the region could get better access, such as borrowing or the chances of getting a regional deal.

The report also confirmed what Wellington City councillors were told at a briefing earlier this month, where amalgamating with the Hutt Valley and Porirua councils, would cost 20% to 25% of a single year of the councils’ operating expenditure.

Local Democracy Reporting (LDR) is local body journalism co-funded by RNZ and NZ On Air