The Ministry of Defence is to recruit a new force of "cyber reservists" to bolster the uK's online defences.
The first annual update of the government's cyber security strategy disclosed that all three services were now bringing in additional experts to support their work protecting against the growing threat of cyber attack.
Details of the new cyber reserve force will be announced by ministers next year.
The MoD has already established a military Joint Cyber Unit based at GCHQ - the secret electronic communications spy agency - in Cheltenham.
The strategy document said that it was now developing "new tactics, techniques and plans to deliver military capabilities to confront high-end threat".
Publishing the document, Cabinet Office Minister Francis Maude said: "There exist real and growing threats to our interests in cyberspace: these threats have increased concurrently with the growth of the 'internet economy'."
The move comes as officials disclosed that "hostile foreign states and others" had carried out "mapping" of the systems controlling UK critical national infrastructure - such as power and water supplies.
The officials would not name the countries involved although reports in the United States have said Russia and China have carried out similar "reconnaissance" exercises there.
The Security Service, MI5, is now developing and enhancing its capabilities to investigate threats in cyberspace from foreign intelligence agencies and terrorists.
The document empathised, however, that cyber security was not a matter for government alone and that industry and individuals had to play their part.
A survey by consultants PwC found 93 per cent of large corporations and 76 per cent of small businesses suffered a cyber security breach over the past year, with costs running at up to £250,000 for larger firms.
From next spring, the government will launch a series of public awareness drives aimed at improving online safety for consumers and small businesses.
A new "cyber confidence tracker" will regularly track "perceptions and behaviours" to ensure the message is being delivered as effectively as possible.