The re-opening of the Taranaki Cathedral - New Zealand's oldest stone church - is a step closer following the granting of resource consents for its earthquake strengthening and refurbishment.

Photo: RNZ / Robin Martin

The Cathedral Project's remediation and design manager Jenny Goddard said the New Plymouth Council's decision was an important milestone in the five-year $15 million redevelopment.

"It gives us surety around the design for the remediation of the cathedral and enables the drawings to now be developed further by a range of specialists and consultants involved in the engineering, historical and conservation aspects of the work. We will then be in a position to apply for building consent."

Bishop Selwyn established the historic St Mary's Church in New Plymouth in 1842 and it was consecrated as Taranaki Cathedral Church of St Mary's in 2010. It has been closed for safety reasons since February 2016.

Ms Goddard said the earthquake strengthening and refurbishment was the first phase of a three-stage project to create a cathedral precinct on the site, incorporating a new atrium and the adjacent vicarage.

She said months had been spent on the resource consent application to ensure the work had as little impact as possible on the historical significance of the building and site.

"Taranaki Cathedral is an historical building within a graveyard that includes a number of notable trees, so protecting those features, and using like-for-like materials and concealing as much of the strengthening work as possible is a priority of the remediation work."

It is expected that as a result of the strengthening, the building's earthquake rating would improve from below 15 percent of New Building Standard to at least 67 percent.

"The overall design approach brought to the project has been to provide as light a touch to the structure and grounds as possible even where this significantly increases the complexity and cost of the project," the NPDC noted in its decision.

"This approach is to be commended (as it provides something of a best practice blue print to be applied to other heritage buildings that require strengthening) and is warranted given the building's significance."