The chance of a major earthquake hitting Wellington is smaller than previously thought, say scientists.

Russ Van Dissen from GNS Science said there was only a 10 per cent chance of the Wellington faultline rupturing and causing a big quake within the next century, compared to the 30 per cent chance previously thought.

But he said there was no room for complacency.

"There are other earthquake sources in and around the region that can produce significant damage and loss."

The other faultlines are at Ohariu and the Wairarapa.

The assessment was given as Wellington City Council announced an $80 million package to strengthen buildings over the next decade.

Council programme director for earthquake resilience Neville Brown said Wellington had been through four large earthquakes, a 7.5 magnitude in 1848, an 8.2 magnitude in 1855 and 6.8 and 7.2 events in 1942.

The first was centred in Marlborough and the rest in the Wairarapa.

"We learnt from those events. In 1848, when the 7.5 quake hit the city, there were three deaths and many buildings were damaged. So people rebuilt in wood."

He said the larger earthquake that struck in 1855 was the largest recorded in New Zealand, and one death occurred.

"In the 1942 earthquakes, many chimneys fell down and many of these were never replaced. The consequence of this is that in a future earthquake we will be dealing with fewer damaged chimneys."

Between 1968 and 2003, about 500 buildings in the central city had been demolished or earthquake strengthened.

Modern building codes dictate that buildings in Wellington must be built three times stronger than those in Auckland where the risk of a quake is far less, he said.

However, more than 2500 buildings are earthquake prone and another 3395 have still to be assessed.

"One day, Wellington can expect a big earthquake. It might be today, or it might not be for 500 years. What happened in Christchurch has made real for us all what the impact of a major earthquake might be."

- APNZ