The Ministry of Defence dealt with more than 1,000 cyber attacks last year, according to defence secretary Liam Fox.
In a speech at a London Chamber of Commerce and Industry dinner, Fox said that the MoD was a "prime target" for cyber attacks from criminals and foreign intelligence services.
"There is a continuous battle being waged against us, day in and day out.
"Our systems are targeted by criminals, foreign intelligence services and other malicious actors seeking to exploit our people, corrupt our systems and steal information. To give you an idea of the challenge, last year the MoD blocked and investigated over 1,000 potentially serious attacks," Fox said.
The attacks are mainly in the form of spam emails, which also include attempts to steal information from the MoD's computer systems.
Fox also warned that the cyber threat was growing in "scale and sophistication" and that "my department is a prime target". He said that security incidents in cyberspace had more than doubled between 2009 and 2010.
The government has been keen to highlight the scale of the cyber threat to the UK.
Last month, Chancellor George Osborne revealed that hostile intelligence agencies made hundreds of attempts to hack into the Treasury's computer system last year. Armed forces minister Nick Harvey then acknowledged that the UK has a cyber weapons programme, which was followed by the MoD announcing plans to hire 'hundreds' of cyber security experts to fully embed cyber capabilities in the UK's defences.
Referring to defence company Lockheed Martin's recent cyberattack, Fox said that the government's suppliers also need to be aware of the cyber threat.
"There is no Maginot Line in cyber space as recent high profile attacks on defence contractors have shown. Our national intellectual property in defence and security industries is at risk from a systematic marauding.
"Increasingly we will worry about how seriously our suppliers take account of the cyber security threat when we are placing our business," he said.
The Cyber Security Operations Centre at GCHQ and the Cabinet Office are understood to be leading the development of the cyber weapons programme. Major General Jonathan Shaw has already been appointed to lead the Ministry of Defence's Defence Cyber Operations Group over the next four years.
As part of last year's Strategic Defence and Security Review, prime minister David Cameron confirmed that the government would allocate £650 million over a four-year period to fight against cyber attacks. The government also detailed cybercrime as a 'tier one' risk to Britain, alongside terrorism, international crises and natural hazards.