A state of emergency in New Zealand South Island city of Christchurch has been extended until Wednesday following the magnitude 7.1 earthquake on Saturday.

Much of the ruined city remains cordoned off on Monday morning, while search and rescue teams assess buildings for damage.

The main rail line south of Christchurch has reopened, however, following repairs.

A 12-hour curfew covering the center of Christchurch was lifted at 7 a.m. on Monday.

It was the second night that police have maintained a lockdown of the central business district.

Another curfew in the city is intended on Monday, from 7 p.m. - 7 a.m., for the public's safety.

Inner-city Christchurch remains off-limits to an estimated 50, 000 workers on Monday and the city's mayor has warned it could be months before life returns to normal after the shattering earthquake.

Workers in the central city are being told not to go to work and city buses are cancelled.

All schools in Christchurch, Selwyn and Kaiapoi are closed on Monday. Canterbury University is closed until at least Sept. 13.

Dozens of aftershocks are still being felt as people confront the massive task of cleaning up.