Death toll from Christchurch earthquake expected to reach 300

New Zealanders are waking to what is being described as their darkest day as the death toll from the Christchurch earthquake could reach as high as 300 today.

Search and rescue teams were last night scouring the destruction in Christchurch in search of survivors, but the earthquake death toll is expected to rise as more bodies are found in the rubble.

At least 65 people, including children, have been confirmed dead   a number which Mayor Bob Parker said could double.

Last night, other reports put the death toll as high as 300.

Parker said 120 people were believed to have been pulled alive from the debris.

This latest report from Radio New Zealand.

Urban search and rescue teams were last night concentrating efforts on six downtown sites where at least 100 people were trapped.

Parker said there are dozens of people in peril who may not be able to be saved.

Unlike the city's previous big earthquake, which hit in the early morning as people slept, yesterday's magnitude 6.3 jolt struck at 12.51pm as downtown workers and shoppers enjoyed the lunch hour.

The violent shaking caused chaos on the streets as buildings crumbled. Witnesses saw people covered in bricks on inner-city footpaths.

Tearful survivors wandered the streets, dazed and bloodied.

Other survivors trapped inside demolished central city structures could be heard yelling as they waited to be rescued.

Some put signs up at the windows saying "HELP".

While yesterday's earthquake was less powerful than the magnitude 7.1 disaster in September, it was only 5km underground, making it far more violent.

The September quake was 33km deep.

Aftershocks continued to rock the city nearly every hour, and giant plumes of smoke and dust clouds hung in the air.

At a press conference last night, Deputy Prime Minister Bill English revealed that Prime Minister John Key arrived in the city to scenes of devastation.

English said these may indeed be New Zealand's darkest days.