The rebuilding of Christchurch, New Zealand's third-largest city, which suffered a major earthquake in February 2011, will cost a total of 40 billion New Zealand dollars ($33.9 billion), an increase of 33 percent from a December estimate, Prime Minister John Key said Sunday.

"This is the largest and most complex, single economic project in New Zealand's history," Key said in the statement. "The scale of the rebuild is unprecedented. That always meant that it would be difficult to get an exact handle on the total estimated cost straightaway."

The city and the surrounding Canterbury region suffered a magnitude 7 earthquake in September 2010 that damaged homes and roads, with no loss of life. In February 2011, even as the effects of the first shock were being repaired, another temblor hit, killing 185 people and wrecking much of the city center.