The company responsible for the implosion of Christchurch's earthquake damaged Radio Network House and the Central Police Station has been chosen to demolish the earthquake damaged Molesworth St building in Wellington.

The quake-damaged office tower at 61 Molesworth St is to be demolished by the property's owner, with work starting today.

Ceres NZ has been contracted to tear the building down.

Part of the building was substantially damaged in last Monday's earthquake and there are concerns it could collapse.

Advertisement
Advertise with NZME.

Ceres NZ will "deconstruct" the nine-storey building using an 85-tonne CAT 385 "ultra-high-reach" excavator with a boom that, when fully extended, has a reach of 15 storeys.

A hydraulically-powered demolition shear at the end of the excavator's boom will chew through the building's concrete and steel structure. The procedure is relatively quiet, to minimise disturbing the surrounding neighbourhood.

The dangerous condition of the site means no one will be allowed to enter the building before demolition starts.

Work to demolish the building is expected to take about two weeks, weather permitting.

However, the start of the work is largely dependent on how long it will take to turn off electricity, gas and other services to the building.

The initial focus of the demolition is planned on the Molesworth St facade of the building and then work progressively to the rear of the site. It is hoped that this approach will reduce the cordon around Molesworth St to vehicles and pedestrians within around a week of demolition work starting.

This will allow more buildings, for example the Embassy of Thailand and NZ Rugby headquarters, to be reopened.

The excavator has been extensively used to demolish many of the Christchurch buildings damaged during the February 2011 earthquake.