The strongest earthquake to hit near Wellington in 70 years shut down much of the capital's CBD on Monday, including most bank branches, but it is expected to open for business for Tuesday after checks confirmed damage was mostly superficial.The 6.5 magnitude earthquake was centred in the Cook Strait about 50 kilometres south of Wellington. It struck just after 5pm on Sunday evening, breaking windows, knocking loose masonry and shaking loose wall panels in 35 buildings, including the main Wellington offices of NAB's BNZ.BNZ's five-storey Harbour Quays building on Wellington's reclaimed waterfront suffered extensive internal damage to ceiling panels and from water damage caused by burst pipes. It was opened in 2009 and has been the centre for 1,100 BNZ staff in Wellington, although BNZ's national headquarters in now in Auckland."Water damage has affected most parts of the building," BNZ's CEO, Andrew Thorburn, said in an email to staff published on BNZ's Facebook page on Monday evening. "We're now awaiting formal engineering clearance and are meeting with a construction firm to work on a programme of works to clean up the building," he said.Most bank branches in Wellington's CBD and the surrounding area stayed closed on Monday but were expected to re-open on Tuesday, after engineering inspections and repairs of minor damage. Government departments and most commercial premises were also closed for business.CBA's ASB said on Monday evening that five of its Wellington branches were closed until further notice and four of its main business and processing centres were also closed. Westpac said all its Wellington branches had been checked and would re-open on Tuesday. ANZ said late on Monday that 12 branches remained closed while a further 10 branches closed on Monday would re-open on Tuesday. It said capacity from its Wellington call centre was limited because of the earthquake.The Wellington earthquake, although nominally larger than the Christchurch quakes of 2010 and 2011, which caused NZ$40 billion of damage, has been much less disruptive because it was 25 kilometres deep and almost twice as far from the city. The Christchurch earthquakes were shallow and just a few kilometres from the CBD.