The latest aftershock to hit Christchurch has apparently caused at least one building to collapse.

Police have confirmed a building on the corner of Stanmore and Worcester Street has collapsed and while there were reports that people were feared trapped inside the building it has subsequently been cleared.

TV3 also reports an ambulance was sent to Latimer Square where people are also feared trapped.

Police have confirmed two people were trapped in St John's church but firefighters have successfully rescued them and they are being treated for their injuries.

St John's Ambulance has confirmed they have been involved in transporting six people so far to Christchurch hospital.

"The injuries were as a result of falling building material," a press release said.

"We had several ambulances operating in the city and some on stand by straight after the earthquake.

"111 calls to the communications centre have now returned to normal levels."

Just after 1pm the violent 5.5 magnitude quake struck the city at a depth of just 11km, 10km east of Lyttleton, 10km north-east of Diamond Harbour and 10km east of Christchurch.

GeoNet reports another aftershock followed soon after at 1.28pm

"It was very frightening. I am very worried about some reports of injuries coming in," Mayor Bob Parker told NewstalkZB.

Parker said the major concern was for people who may have been in the city centre working around already damaged or semi-destroyed buildings.

"There are people in there all the time working on the demolition process," he said.

"If we ever needed a reminder of why it is we do that we just had one today."

A caller to NewstalkZB described the Centra Hotel appearing to be on a slant after the latest quake.

The same caller said the quake felt bigger than it was and was similar to the one that destroyed the city in February although shorter.

Schools have been evacuated and closed along with the University and the University halls of residence have been evacuated.

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