Christchurch earthquake: Your stories
New Zealand's prime minister says at least 65 people have died after a 6.3-magnitude earthquake hit Christchurch.
John Key said the toll was expected to rise further, adding: "We may be witnessing New Zealand's darkest day."
BBC News website readers from New Zealand who have been affected have been contacting the BBC.
Rhys Taylor, Christchurch
I was at work in an office block in Christchurch, when the earthquake hit.
We all rushed out of the building and on to Oxford Terrace, which is about 50 metres away from the city's hospitals.
I heard lots of sirens and saw emergency vehicles.
But many people who were injured were being transported to the hospital on the top of normal cars or on the back of trucks.
Civilians and police really pulled together.
The roads here are a mess; this earthquake is a lot worse than the one that hit us back in September last year.
Doug Williams, Christchurch
The centre of Christchurch is a scene of utter devastation.
I'm a librarian and our library (in Fendalton, a suburb in North Christchurch) experienced significantly more damage this time than during the last earthquake. The structural damage can be fixed but the library will have to close for a while.
I was in the library when it hit. The books started falling off the shelves and some people began to panic. Some were running out of the library, while others were trying to hide under the desks.
There were people of all ages in the library - one of my colleagues had only just finished a story time session an hour before.
We took everybody outside afterwards but still had to deal with the aftershocks.
We saw one woman who was quite bloodied because she had been in her driveway when a chimney collapsed.
The phone lines are cutting intermittently. We've had nine aftershocks already, but in a sense, you do start to get used to them.
Philip Shipley, Lyttleton
I was in one of the office blocks and we'd just had our lunch.
We were having a desk conference and then suddenly all hell broke loose.
The building started shaking vigorously - light fittings were falling off the walls and aircon pumps came off the floor.
There were six of us nearby - we all dived under the desks.
It was much worse than the September earthquake - it seemed to go on for much longer.
I'm quite shaken up. When we went outside afterwards, it was carnage in the streets - brick buildings had collapsed, parked cars were under the rubble.
Aftershocks meant more buildings were coming down.
About 60% of the main street is completely trashed. I'm not sure if it's going to be fixable.
Sally McCann, Christchurch
We are on holiday in New Zealand.
We had just been to the cathedral and called into a cafe in the corner of a quad in the Arts Centre buildings to have lunch when the earthquake started.
We'd just ordered and then there was this incredible rumbling and shaking. Stuff was flying around in the kitchen.
There was a moment when all the earthquake advice flashed through our minds - should we go and stand in the doorway?
It was difficult to walk because the ground was shaking so much.
We did get to the cafe doorway and then there was this incredible crash. Then a turret came smashing down about 12 feet away from us.
We were absolutely covered in dust and completely stunned.
When the shock settled we walked away from the buildings and were absolutely devastated to see the destruction around us.
There was rubble and glass everywhere, whole buildings destroyed, massive cracks in others.
We have now had at least a dozen aftershocks including a strong one about 90 mins after the initial shock.
Tanya Galbraith, Rangiora
I was in a cooking class at my school in Rangiora when the earthquake struck.
It started slowly and then the whole room began to shake. Soon the whole building was shaking and we had to get under the desks until it was safe to leave.
The fire alarms and earthquake alarms went off and the teachers led us all outside to the field where we waited for the Civil Defence to come, but while we were waiting there was a huge aftershock.
People started crying because we were so shocked. It was far worse than the September earthquake.
Grant Beedie, Christchurch
I experienced the September 2010 earthquake and the earthquake today was much much more powerful.
I was at work in an engineering factory in Sydenham. The entire building just shook. We all hit the ground and shut our eyes.
There were loads of things flying off the shelves and massive machines moving about - it was scary. I was almost in tears.
I managed to get back home to my suburb of Hornby before most of the aftershocks, but there was gridlock everywhere.
Not only that, we had to contend with the road being just like a river of sandy sewage water. The journey normally takes about 10 minutes, but it took an hour-and-a-half to get home. It all feels very surreal.
I have a wife and a three-year-old daughter and I wanted to rush home to check they were safe. Luckily my wife picked up my daughter from day-care and they were fine.
Melanie Mellor, Diamond Harbour
It's been a traumatic day. But despite all the pictures, there are a lot of us who are unscathed.
When the earthquake hit at lunch, I was at work, just outside the central business district. We've had so many aftershocks, you almost become a bit blase about it, but this one suddenly took hold of the building and things started falling off desks. The computers were falling off desks. The building literally shook like a jelly.
Every time one of the large aftershocks happened - it seemed like they were going on for a really long time. It was very frightening.
When we got outside we could still see the ground shaking. Then it was chaos, because everyone was trying to leave at the same time - the roads were blocked, the emergency services couldn't get through.
Buildings have disappeared - shop fronts have fallen onto buses, into cars. But we didn't get an idea of the scale of it until we saw it on TV. The damage has been extensive.
People are still trapped, others are out in the open air as hotels are damaged. I feel very lucky.
Christopher Stent, Christchurch
This was a major quake and the city has taken a major hit.
The phone lines and water are not working and the roads are grid-locked as the city is being evacuated.
I work from home and both my computer screen and printer ended up in my lap. The whole house shook. The pictures fell off the wall and it looks a bit like a bomb site.
We weren't expecting it and it hit within seconds. My whole body felt like it was out of control.
I haven't been able to get hold of my son, who is a student at the University of Canterbury, Christchurch. Mobile phones aren't working at all. My wife went to work at a pre-school this morning and I don't know what's happened to her.
We live near the hospital so our power returned quite soon but I don't know what else to expect.