Falling concrete put tunnel users at risk

File photo / Thinkstock

The New Zealand Transport Agency (NZTA) is defending itself against criticism over the length of time it took to ensure the safety of Mount Victoria Tunnel in Wellington, after a report suggested users were at risk of being hit by falling concrete.

The report, released to Radio New Zealand under the Official Information Act, was prepared for NZTA in July last year.

It said the false ceiling, or plenum slab, "should be removed at the earliest opportunity'' as "the risk of collapse in the next two years is high''.

"The plenum slab has little, or no, residual service life: this statement is mainly based on the amount of corrosion damage and deterioration present and the increasing frequency of pieces of concrete falling from the slab soffit and the associated risk to users.''

However, the tunnel upgrade did not begin until April this year and took until earlier this month to be completed.

Mount Victoria Residents' Association president Elaine Hampton said NZTA's delayed response had put people at serious risk and the tunnel should have been closed immediately.

"Over a thousand people a day walk and cycle through that tunnel - mothers with children take them to school through it - it's just not safe.''

Ms Hampton also criticised NZTA for not informing locals of the potential hazards identified in the report.

"I'm sure that they've been extremely economical with the truth.''

The report also recommended that NZTA increase the frequency of tunnel inspections to mitigate any risks, which it did.

NZTA Wellington state highways' manager Rod James disagreed that the response had been slow.

"We needed to work out how we were going to remove the ceiling, we needed to do the design work around it and my understanding ... is that we effectively did this work as fast as we could.''

Mr James said it had also been established that the ceiling was more structurally robust than the report suggested.

"Some of the things that have been suggested are that we have allowed people to use that tunnel when it was unsafe. If we had come across anything during our inspections we would have closed the tunnel, of course we would.''