The agency set up to counter cyber attacks on New Zealand says the number of reported attacks may be less than half the actual number, with many organisations unaware they are victims.
The National Cyber Security Centre advises organisations on how to recognise and protect themselves from cyber invasions.
The centre says during 2011, there were 90 reported attacks on the computer systems of government departments and operators of critical infrastructure such as telecommunications.
The director of the Government Communications Security Bureau, which overseas the centre, believes the real total could be more than 180 - but organisations do not realise that they have been targetted.
Ian Fletcher says the role of the National Cyber Security Centre is to advise organisations on how to recognise cyber attacks and protect themselves.
He says there are three main reasons for attacks.
"It ranges from people who've got criminal motives and are interested in making money right the way through to people who've got particular issues that they're looking to pursue, or are perhaps looking to obtain information that they can turn to some advantage perhaps because it's got some kind of commercial value."
Mr Fletcher says it is becoming more important that companies know how to protect themselves.
"If we have an increasingly knowledge-based economy in New Zealand, then protecting that knowledge, protecting our country's intellectual property becomes really quite important if New Zealand's to continue to be a safe place to invest.
"And if we're able to attract the kind of commercial partners who are going to want to place their information here, then we've got to kind of keep up."