An engineer's report on the TSB East Stand at Yarrow Stadium in New Plymouth doesn't have much good to say about it.

It might be cheaper to build an entirely new TSB East Stand at Yarrow Stadium than bring the existing one up to earthquake standard, an engineering report suggests.

A report on the earthquake-prone stand at New Plymouth's rugby stadium was carried out by structural and civil engineers Tse Taranaki & Associates in December.

The report, obtained through an official information request, is highly technical but includes a damning one page executive summary.

Andy Jackson/STUFF The stadium underwent some earthquake strengthening in November 2017, shortly before it was shut for undisclosed work.

​The New Plymouth District Council (NPDC) has said it would not make a call on the future of the stand until a builder's report on the stand is finalised. This is not expected to be released for at least another month.

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The engineering report, conducted on behalf of the NPDC, rates the stand at just 10 per cent of the New Building Standard (NBS). Structures at 19 per cent and below are classed as Grade E - significantly earthquake prone buildings.

The summary of the report outlined five main areas of weakness, including the foundations, inadequate edge support of precast flooring and columns not isolated from the flooring.

The summary sets out seven types of remedial work that could address the shortcomings, but questions whether it would make sense to carry out such work.

"It is questionable whether the extent of remediation required is economic in comparison to that of replacement costs," the report said.

"Remediation of the building may not realistically achieve 100 per cent NBS or be as robust as a replacement structure."

Owned by the Taranaki Stadium Trust and controlled by Taranaki Regional Council, Yarrow Stadium is operated by NPDC as an event venue under a management agreement with the trust.

In August 2017, NPDC announced a $2.86 million upgrade of the main stand's hospitality area and some earthquake strengthening work to be completed by September.

At the time council said the venue met earthquake standards and there were no known issues with the main stand.

But in November the East Stand, which houses Taranaki Rugby's headquarters and a catering company, was vacated until further notice when an independent engineering company told NPDC more work was needed.

It was not revealed what was wrong with the stand.

The report has revealed that Tse Taranaki discovered in November that ground beams in the north-south direction of the stand were not installed.

"This may have been an oversight," it read.

The piles which support the East Stand were said to have a "very low" load capacity, reaching its limit at 8 per cent NBS, due to plastic hinging.

This means seismic-resistant frames would be unable to perform "as originally intended by the designer", the report said.

"The piles have been found to be the critical element.

"The piles also have no ability to share load due to a lack of ground beams in the north-south direction."

The connections of the beams in place were also said to be "below life-safety limits".

The concrete flooring used for the concourse and Legends' Lounge has been found to "behave inadequately" in an earthquake scenario, as discovered by research conducted in Christchurch, the report detailed.

"We believe these shortcomings are likely to be present in the East Stand."

The bleachers, or seating, had an additional three separate issues which were said to result in a floor collapse, significant cracking and reinforcement fracturing should an earthquake occur.

"It is expected that additional assessment will be required if remediation is sought," the report said.

"Nevertheless, these issues are not expected to preclude foundation failure."