New Zealand quake: 'Another blow' for Christchurch

New Zealand's Prime Minister John Key has said the government is committed to rebuilding Christchurch and the surrounding areas following further earthquakes in the city.

The tremors have caused at least one building to collapse, four months after a powerful earthquake which destroyed hundreds of buildings and killed 181 people.

Mr Key said the quakes were "another blow to the Christchurch residents, who have already endured so much".