"Thankfully we haven't experienced any of this current strain, but we must be vigilant because it could come to Northern Ireland at any point and it could have infections in our systems at the moment that just haven't activated", said Det Ch Insp Grant.
We've seen the rise of ransomware becoming the principle cyber threat I think.
There is no evidence that patient data has been compromised in the hack which affected around 1% of computers in the NHS in Scotland, the Scottish Government said.
He added: "The trust's security measures that we have got in place are stable and still holding firm".
As the highly publicised Wana Decryptor or WannaCry ransomware attacks continue to hit businesses, the Australian Government has revealed the number of local victims had reached 12 and more were suspected.
"This means that as a new working week begins it is likely, in the United Kingdom and elsewhere, that further cases of ransomware may come to light, possibly at a significant scale".
Over the weekend, the ransomware has hit systems in more than 150 countries, including Russian Federation and the United Kingdom, in one of the most widespread cyber attacks in history. At least some of those emails appeared to be messages from a bank about a money transfer. Ransomware viruses usually infect a pc through an email attachment.
A top Microsoft executive partly blamed the USA government for the WannaCry ransomware attack, saying hackers found a crucial Windows vulnerability in data that had been stockpiled by the NSA.
FedEx, Nissan, and the United Kingdom's National Health Service were among the victims.
Hospitals throughout England had to turn away patients from regular appointments and surgeries due to the first attack.
There is still no evidence any of our hospital systems were affected and we are completely confident no patient data was involved.
Wainwright warned the healthcare sector "in many countries" was particularly vulnerable, but that all organizations should ensure they prioritise cyber security and update their systems.
Microsoft released patches last month and on Friday to fix the vulnerability that allowed the worm to spread across networks, a rare and powerful feature.