Speedy European evidence-sharing about cyber crime may be endangered by a no-deal Brexit, a police officer in Northern Ireland has warned.
European Investigation Orders (EIOs) allow the PSNI to access material within 90 days.
The number of internet-related crimes has increased significantly in recent years but the amount of resources devoted to tackling it is being outstripped, Detective Sergeant Darren McCracken said.
"If we leave as a result of Brexit we no longer have access to EIOs to obtain information within 90 days," he said.
He said that was a fast turnaround in the world of law enforcement.
Investigators can contact firms directly for intelligence-gathering but for court action the official channel is essential, he said.
"If Brexit happens we are no longer part of a European treaty. We may not have access to that."
He was part of a panel at the first UK Finance Festival organised at the Titanic Belfast visitor centre.
Det Sgt McCracken said there was a lack of willingness to engage with law enforcement by companies because of fears of publicity causing reputational damage.
He noted willingness to report for information purposes but evidence-gathering for criminal action was more difficult.
He added that a lot of people feared an investigation would enter the public domain.
"We focus on businesses that will engage with ourselves."
He said crime types are changing and become more complex when they include suspects based in North America.
"The demand is massively outstripping [supply], there is a huge volume of demand on our service."
Companies often contact police after they have been the victims of an attack, he said, which can be too late.
If they can educate people to prevent the crime then officers could focus resources on criminals better, he added.
He reiterated the importance of good cyber-security for businesses: "There is a huge volume of business email compromises that could be prevented."
The conference was organised by UK Finance, the trade body and collective voice of the UK's banking and finance industry.
It represents more than 250 firms across the industry and acts to enhance competitiveness, support customers and facilitate innovation.
Ian Burgess from UK Finance discussed the importance of public-private partnership in addressing cyber threats against the finance sector.
He said: "A rising tide lifts all ships."