"As Iain Lobban, the Director of GCHQ, said recently, we have seen the use of cyber techniques by one nation on another to bring diplomatic or economic pressure to bear," said Harvey.
"The integration of cyber and physical attack would seem to be the most likely use of cyber in the military sphere. We must therefore win the battle in cyber space, as well as the battle on the ground."
By recognising these two types of attack as connected rather than separate, we could better deal with the threat, according to Harvey.
The minister admitted this was no easy task to take on but said it was still a "human domain" driven by "human behaviour and motivations" so we should take what we know about that and project it onto the fight against cyber crime.
However, Harvey added, no matter how big the threat was, it would not replace "boots on the ground."
Last month, it emerged a new UK Defence Cyber Operations Group to combine cyber and physical activities will be created to both protect our nation and to research ways of using technology to complement the military. But, due to the lack of borders in cyber criminal activity, the UK will work closely with NATO.
With physical attacks, international law deems when it is appropriate to retaliate. Harvey believed this should be the same case with cyber attacks.
"For traditional domains, we assess the act, its effects, and the whole context to determine whether it constitutes a breach of international law," he said.
"We then judge what the necessary and proportionate response should be, applying well established legal principles. Why should assessing and responding to a cyber attack be different?"
Harvey concluded: "I believe we must recognise that actions in cyber space should be governed by the same principles of international law which already act to check the worst extremes of state actions in the real world."
"This is what I believe is required if we are to protect the enhanced freedom of opportunity that the digital age can provide."
