The 7.8 magnitude quake last Monday was widely felt and cut off the seaside tourist town of Kaikoura.
"This week's disaster struck in more lightly populated areas but damage to infrastructure has been severe," said Citibank economists in a research note.
Prime Minister John Key said earlier this week the damage bill would be about $2 billion, although he cautioned that was only an early estimate. Finance Minister Bill English told parliament the damage was "relatively localised".
Catastrophe modelling firm AIR Worldwide said the total for insurance losses - which excludes losses to land, infrastructure or cars - would be between $1.15 billion and $5.3 billion.
Most residential damage would be covered by the government-owned insurer, the Earthquake Commission, which is backed by $4.7 billion in reinsurance, AIR Worldwide said in a statement.
In 2011, an earthquake in Christchurch, the South Island's largest city, killed almost 200 people and required a $40 billion rebuild.
More than 1000 tourists and residents have been evacuated from Kaikoura, a whale-watching base that draws visitors from all over the world.
Helicopters have flown provisions from navy vessels anchored offshore and military trucks have finally reached the town.
Relief efforts by sea, air and road would continue as roads remain shut to the public.
"Our people are going to be there for a very long time," a spokeswoman for the New Zealand Defence Force said.
Warships from Australia, Canada and the United States, in New Zealand for the Royal New Zealand Navy's 75th anniversary, have been assisting with Kaikoura's recovery.
This week's quake damaged as many as 60 buildings in the capital, Wellington, on the North Island some 150km to the northeast of Kaikoura.
That included serious structural damage to three relatively recently constructed multi-storey buildings, one of which engineers said would have to be torn down.
The Government said it would investigate why the newer buildings had been unable to withstand the quake.
