KEY POINTS:
Residents of one of Auckland's most exclusive streets - including All Black coach Graham Henry - have been warned to prepare an emergency kit as unstable ground threatens their multi-million-dollar clifftop homes.
The Auckland City Council has sealed off a large part of Cliff Rd in St Heliers to repair huge cracks and reduce the risk to properties.
The street boasts panoramic views of the Hauraki Gulf, but an earth movement of less than 30cm could cut utilities and significant movement would increase risk to properties.
A cordon is in place to prevent public access and residents have been told evacuation is a possibility.
Council construction project manager Kevin Stevens said the cracks were discovered along a 200m stretch of road and footpath.
Graham Henry refused to comment to the Herald on Sunday but did say he was pleased with the council's actions. "We've always been very happy with what's happening."
A report by environmental engineering consultants Tonkin and Taylor blamed heavy rainfall and said ground movement could cause a drop in the road surface in the next six to 12 months.
"Such movement would prevent access to the properties along Cliff Rd and would require significant remedial works to damaged services."
While stating the risk to property is currently low, the report added: "This risk would increase once significant movement occurs."
Work has already started on upgrading an existing retaining wall further down the road, near the St Heliers shops.
The council started injecting the latest cracks with a mixture of hot liquid and self-adhesive bitumen after invoking emergency provisions of the Resource Management Act to seal off the affected area. It will build a second $4 million retaining wall at the latest troublespot, with work not due to finish until December at the earliest.
The problems are another blow for the street's wealthy residents.
They have previously complained about youths congregating at nearby lookout Achilles Pt to drink and take drugs, and the sexual antics of male sunseekers at the bays and beaches beneath the St Heliers cliffs.
The latest setback was outlined at public meetings at St Heliers library, when residents were told to ensure they had a torch, battery-powered radio and cellphone ready.
Graham Henry's wife Raewyn said she had no such provisions in place.
"I will be more worried about what to do with my cats," she said.
She said the couple's home failed to sell at auction in March and they had taken it off the market until the engineering work was finished.
A neighbour said the loss of phone lines would be dangerous because mobile coverage on Cliff Rd was poor.
Auckland University geotechnical engineer Dr Michael Pender said the problems on Cliff Rd were common in coastal Auckland, which had a lot of "rather attractive cliffs in sandstone and siltstone". "The sea eats away at the cliff and every now and again a bit drops off." Dr Pender said the recent heavy rain wouldn't be helping.
"Some people might argue that human construction activity has made things worse."
