Aftershocks resulting from a series of powerful earthquakes in New Zealand's South Island left at least two dead and triggered a tsunami warning, a report said.

The first event, a 7.8-magnitude quake, struck just after midnight Monday near the coastal community of Kaikoura, 93 km northeast of the city of Christchurch, CNN reported, citing the US Geological Survey.

It triggered waves of 2.49 meters (8 feet) above usual tide levels, the highest New Zealand had seen in at least 38 years, Philip Duncan of Weather Watch New Zealand said.

The initial tsunami warning was lifted but temblors continued Monday afternoon, the report said.