A strong new earthquake with a magnitude of 6.2 struck New Zealand's South Island today, hours after a more powerful quake killed two people and damaged buildings along the east coast of the South Island. <br/><br/>Meanwhile, rescuers were scrambling to reach the epicentre of the last night's earthquake that killed at least two people and sparked a tsunami alert that sent thousands fleeing for higher ground. The jolt, one of the most powerful ever recorded in the quake-prone South Pacific nation, hit just after last night near the South Island coastal town of Kaikoura. <br/><br/>Authorities downgraded the tsunami after four hours but said risks remained. In a related development, Prime Minister John Key cancelled a trip to Argentina today and said he wanted to stay at home until the scale of the quake's destruction was known.