The New Zealand Stock Exchange (NZX) said on Monday that its website collapsed due to a cyber attack. The NZX said in a statement that the stock markets were to open on Monday morning under new arrangements, reports Xinhua news agency.
But shortly after 10 a.m., the NZX's main website collapsed before being restored an hour later.
An NZX spokesman said that although the cyber attack affected the website, trading continued as usual.
In the statement, NZX Chief Executive Mark Peterson said that NZX continued to work closely with its network service provider Spark and national and international cyber security partners, including the Government Communications Security Bureau (GCSB), as it has from the outset.
It has also been working Akamai Technologies - one of the world's leading cyber defence experts - to implement additional measures.
"NZX has been advised by independent cyber specialists that the attacks last week are among the largest, most well-resourced and sophisticated they have ever seen in New Zealand," said Peterson.
Trading on the New Zealand stock market was disrupted on last August 25, 26, 27 and 28 as a result of a sustained cyber attack on NZX.
The type of cyber attack was known as a distributed denial of service attack (DDoS), which overwhelms the online service rendering it inoperable.