Christchurch's old Police building on Hereford Street will likely be brought down by explosives.

Demolition has begun on the multi-level building, but a rigorous programme to remove asbestos has to be completed before it can be fully taken down.

Director Building Control and Rebuild Peter Sparrow says any concerns in that regard can be officially laid to rest.

"What they have to do is through there asbestos removal programme that can provide dome substantial testing, both within the building and outside the building to prove that there is no remnants of asbestos left."

It'll be the second Christchurch building to be imploded post-quake, following demolition of the Newstalk ZB building in 2012.