Computer experts are warning a type cyber crime called ransomware could "wreak havoc" on computer systems in 2016.
Ransomware is a type of malware that denies access to a computer until a ransom is paid. Individuals are targets, but so too are businesses, government departments and even law enforcement agencies.
The malware is activated after the computer user clicks on a compromised website, or opens an email sent by the criminals.
The targets are often small businesses or government agencies that do not have sophisticated computer protection.
Hackers recently took control of a Hollywood hospital's computer network. They demanded 40 bitcoins, worth around US$17,000.
But the hackers have also taken control of police departments' computer systems.
"To pay or not to pay, will be the question fuelling heated debate in boardrooms," a US think tank, the Institute for Critical Infrastructure Technology, recently said.
"Ransomware is less about technological sophistication and more about exploitation of the human element. Simply, it is a digital spin on a centuries-old criminal tactic."
The advice from law enforcement is not to pay the ransom. But it seems that a growing number of victims are paying up.
The institute says research by Symantec indicates that US$10,000 is the "sweet spot" for the hackers. That's the amount organisations are willing to pay, but it is less than the amount that would prompt an FBI or Department of Homeland Security investigation.
The institute believes that individuals and organisations need to be more vigilant, and it is also calling for more information-sharing between agencies.
New Zealand's National Cyber Security Centre (NCSC) recorded 190 cyber security incidents in the 12 months to June 30, 2015.
GCSB acting director Una Jagose says 114 were identified as targeting government systems and 56 targeting the private sector. The other 20, the targeted sector was not identified in the reporting.
The total number of incidents is slightly lower than for the 12-month period to December 2013, where 219 were recorded. But Ms Jagose says this is likely to be due to changes to recording and reporting practices, rather than a reduction in incidents.
"In fact, I believe the reverse to be true and that serious incidents are continuing to increase. Over the past few months the NCSC incident response team is recording an average of one serious incident a day."
Of total incidents recorded by the NCSC for 2014/15 period, spear phishing made up 30.5 percent, with 58, followed by network intrusion/compromise with 21.5 percent (41 incidents) and botnets, 9.5 percent (18 incidents).
It says denial of service and drive-by download incidents were both equal at 5.8 percent, with 11 recorded incidents each, followed by credentials compromise with nine.
The NCSC recorded seven scam/spam incidents in the 2014/15 period, which was just 4 percent of reporting, compared with 30 percent and 31 percent of reporting in the 2013 and 2012 calendar years.
There are ways to try to stay safe and prevent your computer system being hacked:
Netsafe has advice on ways to protect your computer on its website.
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