1. 17.30pm: This concludes our rolling updates. Please check our homepage for story updates as they arrive.
  2. 17.20pm: Today's earthquakes were strongly felt in Ashburton and Methven, causing workers to dive under their desks and shoppers to flee buildings.

    Ashburton Guardian acting editor Erin Tasker told APNZ the newspaper's third floor offices shook violently in the initial quake.

    "Everyone looked at each other, because the building shakes when big trucks and trains go past, but it got stronger and everyone was under their desks pretty quickly," Mrs Tasker said.

    "Then everyone's thoughts turned to Christchurch; it's just devastating to think they're going through it all again."
  3. Raw video: Liquefaction in Christchurch
  4. 16.52: People in Christchurch are reporting another large aftershock on Twitter. Early estimates put it at around magnitude 5.0.

    On nzherald.co.nz's Facebook page, Jacky Lee said he was at the gym when the first large quake hit.

    "One dude said to his mate, he was going to go big in the toilet.

    "Moments later, a huge earthquake came and we all ran out. We were all laughing non-stop, and then became good mates. God bless."
  5. 16.45pm: Following the 3.18pm magnitude 6 aftershock, the power supply to the eastern suburbs of Christchurch and to the rural central Canterbury area around Springston were again affected, Orion chief executive officer Rob Jamieson said.

    He said power has been restored to Springston, but 26,000 customers remain without power in eastern Christchurch.
  6. 16.33pm: GNS Science has recorded the 3.18pm quake as a magnitude 6, centred 10km east of Christchurch in South New Brighton, at a depth of 6km.
  7. 16.28pm: New Zealand Post said there will be no mail deliveries in Christchurch. The Christchurch Mail Centre has been evacuated as a precaution and will not re-open this evening.

    The next scheduled mail deliveries following the statutory holidays will be December 28.

  8. 16.24pm: Prime Minister John Key said Canterbury Earthquake Recovery Minister, Gerry Brownlee, will be heading to Christchurch this afternoon to access the situation.

    “My heart goes out to the people of Christchurch and Canterbury at this time,” Mr Key said.

    “However, residents can be confident that the authorities are onto the situation and government resources stand ready to assist wherever they are needed.

    “The Government’s resolve to work with the people of Christchurch and Canterbury to rebuild remains unchanged following today’s two aftershocks."

  9. 16.21pm: GNS Science is still trying to measure and locate the latest quakes, but the 3.19 is "looking to be larger" than the first 5.8 magnitude quake.

    The United States Geological Survey measure the quake as a magnitude 5.8, and was centred 15km northeast of Christchurch, at a depth of 4.9km. It also said a magnitude 5.3 struck at 2.06pm, 21km northeast of the city at a depth 3.7km.

  10. 16.15pm: Kirsty Quested told nzherald.co.nz she had been stuck on a plane at Christchurch Airport.

    "I'm stuck on a plane on the tarmac, since the first quake at 2."

    She said it was "very frustrating" and that she hoped to be in the air soon.

  11. Air NZ's flight information page has details of disruption to flights using Christchurch Domestic Airport.