The stock exchange has suffered several interruptions this morning, but trading has continued.
The NZX website carrying company announcements has gone down for short periods in the first hour.
Trading on the NZX was halted on four consecutive days last week after its website was overwhelmed by the offshore generated attacks.
The company says it's beefed up its defences in conjunction with the Government Communications Security Bureau and leading global IT company Akamai after last week's offshore based attacks.
Trading has not been disrupted this morning.
NZX chief executive Mark Peterson says it has back up measures to ensure company announcements will be available to investors.
Peterson said last week's attacks were among the biggest and most sophisticated seen in the country.