The minister overseeing the country's spy agencies says the New Zealand stock exchange was warned before last week's attacks that it was going to happen.
The NZX suffered trading halts from cyber attacks last week and faced some disruption today for a fifth day today, after distributed denial of service attacks took its website offline.
Andrew Little, the minister overseeing the Government Communications Security Bureau (GCSB), said the NZX and other institutions received messages foreshadowing the attacks. The earliest warnings came through before attacks on the NZX last week, he said.
"As I understand it, the organisations that came under attack received messages before these attacks saying that they would be attacked."
Asked if any money or ransom was demanded, Little said: "I don't want to go into all the detail, that information is part of the investigation and it's a matter for those organisations".
The attacks bore the hallmarks of criminal actors rather than a foreign state, but their motives were so far unknown, Little said.
"The nature of distributed denial of service attacks is that they harness thousands of computers from around the world to send messages to this particular website and they can stop it functioning, basically," Little said.
"Trying to troll your way through all of that is very difficult. There is an investigation involving including other Five Eyes partner countries...
Little said the names of "state actors" had been used during the attacks, but that it was "looking increasingly likely that the use of those names are a decoy".
Little said similar attacks were taking place in South East Asia and North America.
Fifth day of attacks on NZX
The stock exchange's strengthened systems and back up measures held firm against further cyber attacks today.
The NZX website came under early pressure and had several short-lived interruptions but trading was not disrupted.
The company has beefed up its defences with help from the Government Communications Security Bureau and leading global IT company Akamai after last week's offshore based attacks cut short trading on four consecutive days.
The benchmark top-50 index even managed to briefly set a record high before retreating to close more than 100 points or nearly 1 percent lower.
Meanwhile, the GCSB has issued a set of guidelines and advice to companies to protect themselves against such attacks.