Separately, Belgian minister of foreign affairs Karel De Gucht has told parliament that his ministry was the subject of cyber-espionage by Chinese agents several weeks ago.
"There is not enough evidence to say whether these attacks were sponsored by the Chinese government or not, but it does underline the importance of making computer security a priority," said Graham Cluley, senior technology consultant at Sophos.
In September 2007, the Chinese military was blamed for a cyber-attack which targeted a Pentagon computer system serving the office of US defence secretary Robert Gates.
"Spying has been going on between countries for thousands of years, and it would be foolish to think that countries like China would not take advantage of computers and the internet to assist them in this," added Cluley.
"It is unusual, however, for a nation to accuse another of engaging in this activity, especially when it can be extraordinarily difficult to prove an attack is being sponsored by a government or is a lone hacker acting independently."