A Royal Commission of Inquiry will be held into last month's earthquake, focusing on the collapse of buildings in central Christchurch.
Prime Minister John Key says the inquiry will examine issues to do with the CTV and Pyne Gould buildings where there was significant loss of life.
He says the scope will be wide enough to look also at future building codes and standards.
Mr Key says the Government is determined to get answers as to why so many lives were lost in the earthquake.
He says while the Royal Commission should report within a year, its work will be put on hold if there are criminal prosecutions over the collapse of some buildings.
Christchurch mayor Bob Parker says the inquiry will help the council reach its goal of making the city the seismically safest in the world.
Mr Parker says the only way Christchurch has a future is if it's rebuilt to be the safest and most earthquake resistant city in the world.
The commission will be chaired by the High Court judge, Justice Cooper.
Australian PM to attend memorial service
Meanwhile, Mr Key says Australian Prime Minister Julia Gillard will attend the Christchurch Earthquake National Memorial Service on Friday.
Australian Governor General Quentin Bryce and Opposition leader Tony Abbot will also be there.
Two Australians were among the 166 dead.