Two large earthquakes have rattled Christchurch, prompting the evacuation of public buildings and Christchurch International Airport.

Dozens of people received minor injuries and three unoccupied buildings collapsed when two major quakes, measuring 5.8 and 6.0, hit the city on Friday afternoon.

Four people were rescued by the Coastguard following a rockfall at Boulder Bay, near Taylors Mistake, and one person suffered minor injuries in Eastgate Mall.

The first 5.8 magnitude quake struck at 1:58pm local time (11:48am AEDT), 20 kilometres north-east of Lyttelton.

It was followed by a 6.1 magnitude quake which struck at 3.18pm local time, 10 kilometres east of Christchurch.

Two lesser quakes measured 5.3 and 5.0. The swarm of quakes continued into the evening, adding stress for already quake-weary locals.

Last-minute Christmas shopping and travel was abandoned after widespread evacuations of shopping malls, buildings and Christchurch Airport, and roads around the city became congested as people rushed to get home.

"It was incredibly violent," one caller told Radio New Zealand.

"All the water in my birdbath slopped out and I could hear everything falling over inside. When I walked inside, the cat streaked out the door, ornaments were all over the floor, contents of the pantry were lying on the floor, a little bit of smashed glass and picture frames lying over."

Families were picking up loved ones for Christmas at Christchurch International Airport when the first quake hit.

Reporter Juliette Sivertsen had just arrived home for the holidays and was outside the airport when she heard a loud roar and the cars in the parking building started moving from side to side.

"It's been hugely busy at the airport, a lot of people coming home to see friends and family. Planes are coming in from across the country at the moment and then we have this massive earthquake - it's not quite the Christmas present we'd hoped for," she says.

The eastern suburbs were again hit by significant liquefaction and flooding, which had seen many homes declared unsafe to live in back in February.

Newstalk ZB's Brian Ashby says told of liquefaction in the Queenspark area of Christchurch.

"Again, just literally as we speak wading through water and mud that's bubbled up from under the footpath, under the road, the roads are blocked, we can't get to the house that we are trying to get to, the sun's out, it's a glorious day but under foot it's just an absolute shambles."

Dust rising as a result of the 5.8 magnitude earthquake. Photo: AAP

St John Ambulance says it received around 150 emergency calls and it attended treated about 60 people for incidents such as heart attacks, collapses and panic attacks.

Power company Orion said an estimated 26,000 connections lost power in the eastern suburbs.

The Christchurch City Council has established an Emergency Operations Centre in the city.

Christchurch mayor Bob Parker told TVNZ the quake would add to people's stress as they recovered from the devastating 6.3 quake on February 22 which destroyed much of the central city and killed 182 people.

"It's going to be one hell of a day," he said.

"It has been a long hard road, 15 months ... and people had dared to hope that the aftershocks were over."

"I think there will be more damage to buildings, nothing significant, no major collapses just little bits of more debris."

Evacuated travellers outside the terminal at the Christchurch International Airport. Photo: AAP

"It's terrible timing, you can't underestimate the impact of this on people on the psychological level, they've been exposed to so much and it felt like it was getting better, and it just puts the work back, the repairs back, the rebuild back."

He said water and sewage systems would need to be checked.

It also comes less than two weeks after the Christchurch City Council adopted a draft rebuild plan for the city, following the February quake.

A quake of lesser intensity struck the city in September last year.

Large areas of Christchurch's central business district are still off-limits after the February quake, which toppled the city's famous cathedral, as well as shops, homes and office buildings.

The latest quake caused some large rock falls in the hills around the city but none had fallen onto houses or roads around the nearby port town of Lyttelton which was extensively damaged in the February quake.

"There's not a heck of a lot of buildings left to wreck, to bring down in an earthquake, to be perfectly honest," said the town's chief fire officer, Mark Buckley.

The New Zealand dollar briefly dipped to $0.7725 from $0.7740 in thin trading after news of the quake, before recovering. New Zealand stocks cut pared gains to trade up 0.14 percent.

New Zealand straddles the boundaries of the Indo-Australian and the Pacific tectonic plates and is hit by about 14,000 quakes every year, of which only a small number usually top a magnitude of 5.

Scientists had warned after the February quake that there would be further shakes, probably as large as magnitude 6.

"In coming days the most likely scenario is that there'll be a series of aftershocks in a similar location and they'll gradually drop off," Ken Gledhill a seismologist with GNS Science told TVNZ.