Video: Christchurch police station imploded in spectacular detonation

Christchurch's former police station has been demolished in New Zealand's second ever implosion.

The ex-Christchurch Police Station goes up in a cloud of smoke. Source: 1 NEWS

A thunderous blast from 55 kilos of explosives, drilled into columns of the police station, toppling the building, which was several stories high.

Thousands of people gathered in the city centre to watch the historic event, despite being asked to stay away by demolition company Ceres, "for safety reasons".

Ceres project head Bernie De Vere later described the execution of today's implosion as "according to plan", despite some asking on Facebook why the police station remains were left on a lean.

The live moment of the blast and a subsequent clip of the implosion have been watched by thousands on Facebook and on the ONE News website.

Built in 1972, the Christchurch police station survived being shot in 1974, but was wounded in 2011 by the devastating Canterbury earthquakes.

Today's dramatic demolition follows the implosion of Christchurch's Radio Network House in 2012 - the only other implosion to have been carried out in New Zealand.