Australia's attorney-general on Friday said cyber attacks had become so frequent that government and private networks were under "continuous threat", testing online security defences.
But Robert McClelland declined to single out China, at the centre of hacking allegations from Internet giant Google, saying the "Australian government's position is not to identify a source of suspected espionage."
"The reality is espionage can be unquestionably undertaken by other countries, by organised criminals, or indeed by business competitors," he said.
McClelland said it was "unquestionably" in Australia's interest to stay ahead of the evolving, and mounting, cyber threats, as he announced a white paper on the future of Australia's Internet security to be published in 2012.
"Security agencies are finding malicious activity is increasing to a point where systems in both government and the private sector are under continuous threat," he said in a speech to business leaders on cyber crime.
"The cyber threat to Australia is real, evolving and continuing to test our defences."
Foreign intelligence agencies, criminal organisations and commercial competitors were all to blame, with electronic spying cheap and low risk but with huge potential gains, he added.
Authorities estimate cyber crime worldwide to be worth several times more than the illegal drugs racket.
Woodside Petroleum's chief Don Voelte on Monday said the energy giant had suffered attacks from "everywhere", including eastern Europe, Russia and China, with Shell Australia also admitting cyber assaults.
The computers of Australia's prime minister, foreign and defence ministers were all suspected of being hacked in March, with China under suspicion.
Beijing has dismissed the allegations as "groundless and made out of ulterior purposes."
China also angrily rejected suggestions from Google this week that a cyber spying campaign targetting the Gmail accounts of senior US officials, military personnel, journalists and Chinese activists had originated in China.
Boeing under attack
US aerospace giant Boeing is under "continuous" cyber attack but there has been no breach of its databases, a senior executive said Friday.
The admission by Dennis Muilenburg, the chief executive of Boeing Defense, Space and Security, comes as Japanese electronics giant Sony recovers from a series of online incursions while Google also said it has been hit.
"We, as are other global enterprises, are under a continuous state of cyber attack and cyber probing," Muilenburg said.
"We recognise the reality of global business today, is that cyber attacks are part of business and we've been prepared for that so this is not a surprising environment to us," he told a media briefing in Singapore.
Muilenburg did not want to mention how often the attacks took place or the people behind it but said Boeing's investment to protect its systems from hackers has paid off.
"I can tell you that the defensive capabilities that we've built up are very effective, and give us confidence and our enterprise is secure because of that investment," he said.
Sony last month was forced to shut down some of its online services after the details of more than 100 million account holders were stolen.
And on Thursday hackers claimed to have compromised more than one million passwords, email addresses and other information from SonyPictures.com.
In Thursday's attack the hackers posted lists of thousands of the pilfered Gmail, Hotmail, AOL, Yahoo and other email addresses and passwords on Pastebin, where they were publicly accessible.
Earlier this week Google said a cyber spying campaign originating in China had targeted Gmail accounts of senior US officials, military personnel, journalists and Chinese political activists.