Wellington, Nov 14 (IANS): New Zealand Prime Minister John Key has called off talks in Argentina this week as his government deals with the aftermath of a deadly earthquake.

Key said on Monday that he had postponed a trip to Buenos Aires on Tuesday for a series of meetings aimed at strengthening New Zealand's trade, economic and political ties with South America, Xinhua news agency reported.

However, he would attend the Asia-Pacific Economic Cooperation (APEC) Economic Leaders' Meeting in Peru on November 19-20 if circumstances permitted.

At least two people were killed when a 7.5-magnitude quake centered on the northeast of the South Island rocked much of New Zealand just after midnight on Sunday.

It has been followed by hundreds of aftershocks.

"The situation is still unfolding and we don't yet know the full extent of the damage," Key said in a statement.

"I believe it is better that I remain in New Zealand in the coming days to offer my assistance and support until we have a better understanding of the event's full impact," he said.

"My officials have conveyed our apologies to the Argentine government and I intend to call President Mauricio Macri in the next few days," Key said.

The decision on whether the trip to APEC would go ahead would be made later this week.