At least 10 people were seriously injured when the New Zealand city of Christchurch was shocked by a series of powerful earthquakes on Monday.

The quakes, with the strongest put at a magnitude of 6.0 at 2.20 p.m. local time, damaged buildings across the city, Reuters reported.

Almost four months back, a magnitude 6.3 earthquake killed 181 people and caused extensive damage in Christchurch, which the city is still trying to recover from.

You can draw a picture already of a significant earthquake, Christchurch Mayor Bob Parker told Radio New Zealand. A cloud of dust had enveloped the city after the quakes, he said.

According to Civil Defence, two people had been rescued from a damaged church. There were no further reports of trapped people.

New Zealand's GNS Institute stated that the earthquakes were within the expected pattern after February's tremor and could further trigger fresh seismic activity.  

We would expect a number of aftershocks in the magnitude 4.0 to 5.0 range on the coming days and weeks, said Kelvin Berryman, GNS's Manager of Natural Hazards Research. 

 Since a magnitude 7.1 quake on September 4 last year, Christchurch has experienced a number of strong earthquakes. The cost to rebuild Christchurch after the quakes has been estimated at around NZ$15 billion ($12.2 billion). Prime Minister John Key said the new tremor would probably affect recovery efforts.