Britain's armed forces depend "too much" on information and communication technology to prevent cyber crime.
The UK Defence Committee has urged the Government to come up with contingency plans to prevent cyber attacks.
In its report, the committee said the Government must be more vigorous in its approach to cyber threats, which can often develop quickly and pose serious consequences for the nation's security.
"There is a consensus that cyberspace is a complex and rapidly changing environment," said James Arbuthnot, Chair of the Committee. "It was therefore important for us to consider the implications for UK defence and security. It is our view that cyber security is a sufficiently urgent, significant and complex activity to warrant increased ministerial attention."
"The Government needs to put in place - as it has not yet done - mechanisms, people, education, skills, thinking and policies which take into account both the opportunities and the vulnerabilities which cyberspace presents."
The report concludes that Britain's armed forces are now so dependent on information and communication technology that they could be fatally compromised by sustained cyber attacks.
In November 2011, the UK Government revealed its plans to invest £650m over four years as part of a new National Cyber Security Programme (NCSP) to strengthen the country's cyber security.