Hundreds of displaced people flocked to the Burnside High School evacuation centre last night to take shelter.
Another 300 gathered at the Hagley Welfare Centre after their homes became unsafe to live in.
Civil Defence supervisor Derrick Gregory said the shelters were attracting a steady stream of people and officials were expecting a further 850 throughout the night.
Some of the people were from other evacuation centres which had closed or were too full.
Leeann Charlett was at the doctor's with her 4-month-old granddaughter, Acacia, when the quake hit.
Her first thoughts were to get to St Alban's school to collect her children.
"The whole building was just shaking. Glass was smashing ... I was very stressed.
I didn't know what to think, I was just hoping [my children] were safe."
When the family returned to their home, they found it badly damaged.
"We are mainly here because this little one's not well and there's no power at our house," Ms Charlett said.
She said they could not heat any bottles for the baby and could not get any food.
Ms Charlett's son Dylan, 10, a pupil at St Alban's, said of the earthquake: "It was awesome watching the whole school flood. Everyone just lay on the ground because we were on the bus."
He said about four people in his class cried and he helped his teacher calm down some of the other students.
"My teacher told me to pat everyone on the back, so I did."
Ms Charlett's mother, Susan, was with her when the quake hit because her own home had not been repaired after the big September shake.
Her mother, who has limited mobility because of skin cancers on her legs, was on her hands and knees during the quake.
"It was very awful, really awful. I started shaking, my nerves were going," she said.
Mr Gregory said people were coping quite well under the circumstances.
"A lot of them are doing amazingly well. We have got a few that are completely distraught and a few with a few physical illnesses or problems."
Blankets, pillows and mattresses filled Burnside High School's gymnasium as shaken people prepared for the night.
Mr Gregory said a lot of people were offering beds and rooms in their homes, so they were able to billet people.
But some large groups of people at the centre were reluctant to be separated.
They included an International Tennis Federation group and a Turkish sporting team.
A stream of hot-cross buns, home-baking and boxes of food were donated to the centre, and one person loaned a microwave so victims could have a warm meal.
Sarah-Jane Robinson stayed at the centre with her brother and his four children. She was visiting family in St Alban's when the earthquake struck.
"It was far worse than the September or Boxing Day ones. It was more violent. You just can't explain it, it was so unreal. So violent."
She said she jumped in the car to get to her niece's and nephew's school. The usually 10-minute trip took her an hour and 45 minutes because the roads were so congested.
"We collected the kids and went home. The house was just not safe. There's huge cracks and it's far worse than September. It's really quite badly damaged."
She said it had taken some of her nieces and nephews quite a while to get over the September quake.
"They were traumatised for months and just as we started to get settled and relaxed, this happened."
She said they felt relief that they were safe.
"It's been a long day and a hard day and it's hard not to get upset in front of the kids."
At the Hagley centre, victims huddled together, sharing stories and experiences - some even managed to fall asleep.
A group of four Dutch tourists, who were travelling separately but found one another after the quake, huddled together.
Manouk de Vries, 19, had been going to the city library with her friend Carlijn de Hilster, also 19, when the earthquake struck.
"We were going into the library and the moment we got in, all the lights went off and the glass was falling and people were screaming and we didn't know what to do.
"When it stopped and went away, we asked locals what to do.
"I thought I was dying because you are in a strange country and you don't know anyone," Miss de Vries said.
Miss de Hilster said: "Everybody was screaming and lying on the ground and I thought it wasn't going to stop."
The two girls were meant to fly home today, but all their possessions, including their clothes and passports, are in the hostel in which they were staying.
It was next to the cathedral and was severely damaged.
They had both called home to tell their families they were okay. Their parents knew of earthquake because they had seen it on the Dutch news.
A urology conference was taking place at a conference centre near Hagley Park, and the large group of New Zealand and Australian urologists had just returned from a lunch break when the earthquake struck.
A group of three women attending the conference said a 50cm television screen fell on top of them.
"Some man was very lovely and pushed it off me," one of the women said.
Chantel Doran, a 26-year-old from Brisbane, said lightbulbs exploded and objects crashed around them when the quake hit.
"The moment the shaking stopped, we just grabbed each other's hands and ran," she said.
Another woman at the conference said the area they had just finished having lunch in was covered in glass and broken roof pieces.
A St John paramedic at the centre said staff had treated mostly minor injuries such as headaches, cuts and blisters caused by patients wearing wet shoes.
NZ'S BIGGEST QUAKES
8.2, Wairarapa, January 23, 1855 - The most severe earthquake in New Zealand since systematic European colonisation began in 1840.
7.8, Fiordland, July 16, 2009 - Only 12km deep and on the coastline at Milford near Dusky Sound: the largest earthquake since the 1931 Napier earthquake.
7.8, Hawkes Bay, February 3, 1931 - Until yesterday, the Hawkes Bay earthquake caused the largest loss of life, at least 256, and most extensive damage of any recorded NZ quake.
7.8, Murchison, June 17, 1929 - The massive rumbling of the 1929 Buller earthquake was heard as far away as New Plymouth.
7.8, Marlborough, October 16, 1848 - This was the largest in a cluster of earthquakes that hit central NZ that year.