Defence House on Aitken St will be demolished.

Central Wellington will again be the scene of post-quake demolition as a date is set for Defence House to come down.

While New Zealand First leader Winston Peters claimed as far back as February the Aitken St building would have to come down, the building's owner, AMP Capital, did not confirm this till March.

In a statement on Tuesday, a spokeswoman confirmed demolition - or "deconstruction" - would begin in coming weeks and end early in 2018.

The building suffered "significant damage" in the Kaikoura quake.

Freyberg House, commonly known as Defence House, was officially opened just a decade ago, in 2007.

Wellington City Council compliance manager Mike Scott said Aitken St would be reduced to a one-lane, one-way road for "pretty much the duration" of the demolition.

Mulgrave St - a major entry to the city - would remain open though may have to be reduced to a single lane at times, most likely in the weekends.

A statement from AMP said the announcement it would be demolished followed "a comprehensive consultation process with the Wellington City Council" to ensure work was done to minimise inconvenience to the public.

The seven-storey building has been empty since the November 14 earthquake.