Work is under way on a new, greatly expanded wastewater system for Northland's second largest urban population.

Construction is due to start this week on Kerikeri's $25.6 million sewage treatment plant which will replace the struggling 29-year-old plant on Shepherd Rd.

That facility is at capacity and failing to meet its resource consent conditions.

The cost of its replacement is being subsidised by $7.3m from the Ministry of Health (MoH).

Advertisement

The new plant will treat 1000 cubic metres of sewage a day, or three times the amount the old one can handle, and should be up and running by next March.

Far North District Mayor John Carter said the Kerikeri Wastewater Scheme will bring many benefits to central Kerikeri.

''It is also designed to be expanded in line with growth and could eventually treat up to 2000 cubic metres of sewage a day,'' he said.

The project is the council's largest capital works project to date.

Outside the healthy MoH subsidy, the remaining $18.3m will be funded through rates charged to properties which will connect to the 28.5km of new sewerage pipes — properties in "the area of benefit", under the Far North council's current stance.

Depending on the build's final sums, and whether all the contingencies are used, each will pay around $443 in 2018/19, rising to $1293 in 2019/20.

Properties already in the old scheme will pay operating rates of $499 from 2018/19, while those newly on stream because they are within the expanded network won't start paying until 2019/20.

As new properties come on line, owners will also have to stump up for a one-off connection fee of $734.16.

The council has awarded the plant's construction contract to Broadspectrum (New Zealand) Ltd.

Stage one will involve forming an access track to the rural site, 3km out of Kerikeri, off Inlet Rd. Strict erosion and sediment controls had to be approved by Northland Regional Council to allow the earthworks to be done in the winter season.

United Civil Construction Ltd has nearly completed laying the pipe network which adds an initial 350 properties to the scheme. Their existing septic tanks will be decommissioned once the switch over happens.

The whole project is expected to be completed by mid-2019.